Garments of barrier webs

ABSTRACT

The present invention includes novel barrier webs that have certain desirable physical qualities such as water resistance, increased durability, improved barrier qualities and the like. The present invention further comprises a barrier web comprising a web that has been treated with a curable shear thinned thixotropic polymer composition, the fabric being adapted to be substantially impermeable to liquids, permeable to gases and impermeable to microorganisms. The barrier webs of the present invention are either impermeable to all microorganisms or are impermeable to microorganisms of certain sizes. The present invention also includes fabrics that are capable of either selective binding certain microorganisms, particles or molecules depending upon what binding partners are incorporated into the polymer before application to the fabric.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 08/472,568 filed on Jun. 7, 1995, now U.S. Pat. No. 5,874,164,which is a continuation-in-part of U.S. patent application Ser. No.08/442,983 filed on May 17, 1995, now U.S. Pat. No. 5,869,172 which isincorporated herein by reference, which is a continuation-in-part ofU.S. patent application Ser. No. 08/407,191 filed on Mar. 17, 1995, nowU.S. Pat. No. 5,876,792 which is a continuation-in-part of U.S. patentapplication Ser. No. 08/017,855 filed Feb. 16, 1993, which issued asU.S. Pat. No. 5,418,051, which is a continuation of U.S. patentapplication Ser. No. 07/680,645 filed on Apr. 2, 1991, which issued asU.S. Pat. No. 5,209,965, which is a continuation of U.S. patentapplication Ser. No. 07/319,778 filed Mar. 10, 1989, which issued asU.S. Pat. No. 5,004,643, which is a continuation-in-part of applicationSer. No. 07/167,630 filed on Mar. 14, 1988, and a continuation-in-partof U.S. patent application Ser. No. 07/167,643 filed on Mar. 14, 1988,and a continuation-in-part of U.S. patent application Ser. No.07/167,797 filed on Mar. 14, 1988, and a continuation-in-part of U.S.patent application Ser. No. 07/167,869 filed on Mar. 14, 1988, and allof which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to barrier fabrics. More particularly, thepresent invention relates to barrier fabrics that are substantiallyimpermeable to water, substantially permeable to gases and impermeableor selectively impermeable or permeable to particles such asmicroorganisms, cells, molecules, and the like. The present inventionalso includes articles and clothing made from the barrier fabricsdescribed herein including career hospital garments, incontinent briefsand the like.

BACKGROUND OF THE INVENTION

Barrier fabrics are generally characterized by being impervious topenetration by liquids. There is a class of barrier fabrics which,additionally, are vapor permeable to provide what is termedbreathability. Barrier fabrics are especially useful in the medicalcareer apparel garments. The barrier fabrics in the prior art can begenerally classified as disposable and reuseable. Disposable fabrics aretypically constructed from nonwovens made from light weight syntheticfibers or synthetic fibers blended with natural fibers. Performance ofdisposable nonwoven fabrics in terms of liquid repellency and flameretardancy are quite acceptable. Reusable fabrics are normally woven andmay be constructed from cotton or cotton/polyester blends of a highthread count to provide a physical barrier to prevent or reduce thespread of infectious materials and vectors.

While reusable woven fabrics generally offer more comfort in terms ofdrapeability, breathability, transmission of heat and water vapor,stiffness, etc., and improved (reduced) cost per use, they lack theliquid repellency the market has come to expect on the basis ofexperience with the disposables, especially after repeated launderingsand/or steam (autoclave) sterilizations.

Woven reusable surgical barrier fabrics must meet or exceed the currentcriteria for National Fire Protection Association (NFPA-99) and theAssociation of Operating Room Nurses (AORN) "RecommendedPractices-Aseptic Barrier Material for Surgical Gowns and Drapes" usedin constructing operating room wearing apparel, draping and gowningmaterials. To be effective, the fabric must be resistant to blood andaqueous fluid (resist liquid penetration); abrasion resistant towithstand continued reprocessing; lint free to reduce the number ofparticles and to reduce the dissemination of particles into the wound;drapeable; sufficiently porous to eliminate heat buildup; and flameresistant.

Reusable fabrics should withstand multiple laundering and, wherenecessary, sterilization (autoclaving) cycles; be non-abrasive and freeof toxic ingredients and non-fast dyes; be resistant to tears andpunctures; provide an effective barrier to microbes, preferably bebacteriostatic in their own right; and the reusable material shouldmaintain its integrity over its expected useful life.

None of the fabrics or the fabrics taught in the prior art has thephysical characteristics of (1) being substantially resistant orimpermeable to liquids, such as water, (2) being permeable to gases, and(3) impermeable to microorganisms. In addition, none of the fabricstaught in the prior art teach or suggest fabrics that are capable ofselectively removing or retaining microorganisms or other particles ormolecules from the surrounding milieu.

In the prior art, it has been proposed to treat porous webs, especiallyfabrics, with silicone resins and also with fluorochemicals.Conventional treatments of webs fall into the general categories of (i)surface coatings and (ii) saturations or impregnations.

For example, U.S. Pat. Nos. 3,436,366; 3,639,155; 4,472,470; 4,500,584;and 4,666,765 disclose silicone coated fabrics. Silicone coatings areknown to exhibit relative inertness to extreme temperatures of both heatand cold and to be relatively resistant to ozone and ultraviolet light.Also, a silicone coating can selectively exhibit strength enhancement,flame retardancy and/or resistance to soiling. Fluorochemical treatmentof webs is known to impart properties, such as soil resistance, greaseresistance, and the like.

Prior art fluorochemical and silicone fabric treatment evidently canprotect only that side of the fabric upon which they are disposed. Suchtreatments significantly alter the hand, or tactile feel, of the treatedside. Prior silicone fabric coatings typically degrade the tactilefinish, or hand, of the fabric and give the coated fabric side arubberized finish which is not appealing for many fabric uses,particularly garments.

U.S. Pat. No. 4,454,191 describes a waterproof and moisture-conductingfabric coated with a hydrophilic polymer. The polymer is a compressedfoam of an acrylic resin modified with polyvinyl chloride orpolyurethane and serves as a sort of "sponge", soaking up excessmoisture vapor. Other microporous polymeric coatings have been used inprior art attempts to make a garment breathable, yet waterproof.

Various polyorganosiloxane compositions are taught in the prior art thatcan be used for making coatings that impart water-repellency to fabrics.Typical of such teachings is the process described in U.S. Pat. No.4,370,365 which describes a water repellent agent comprising, inaddition to an organohydrogenpolysiloxane, either one or a combinationof linear organopolysiloxanes containing alkene groups, and a resinousorganopolysiloxane containing tetrafunctional and monofunctionalsiloxane units. The resultant mixture is catalyzed for curing anddispersed into an aqueous emulsion. The fabric is dipped in the emulsionand heated. The resultant product is said to have a good "hand" and topossess waterproofness.

This type of treatment for rendering fabrics water repellent withoutaffecting their "feel" is common and well known in the art. However, ithas not been shown that polyorganosiloxanes have been coated on fabricsin such a way that both high levels of resistance to water by thefibers/filaments and high levels of permeability to water vapor areachieved. As used herein, the term "high levels of permeability to watervapor" has reference to a value of at least about 500 gms/m² /day, asmeasured by ASTM E96-80B. Also, as used herein, the term "high level ofwaterproofness" is defined by selective testing methodologies discussedlater in this specification. These methodologies particularly deal withwater resistance of fabrics and their component fibers.

Porous webs have been further shown to be surface coated in, forexample, U.S. Pat. Nos. 4,478,895; 4,112,179; 4,297,265; 2,893,962;4,504,549; 3,360,394; 4,293,611; 4,472,470; and 4,666,765. These surfacecoatings impart various characteristics to the surface of a web, but donot substantially impregnate the web fibers. Such coatings remain on thesurface and do not provide a film over the individual internal fibersand/or yarn bundles of the web. In addition, such coatings on the websurface tend to wash away quickly.

Prior art treatments of webs by saturation or impregnation also sufferfrom limitations. Saturation, such as accomplished by padbath immersion,or the like, is capable of producing variable concentrations of a givensaturant chemical.

To treat a flexible web, by heavy saturation or impregnation with apolymer material, such as a silicone resin, the prior art has suggestedimmersion of the flexible web, or fabric, in a padbath, or the like,using a low viscosity liquid silicone resin so that the low viscosityliquid can flow readily into, and be adsorbed or absorbed therewithin.The silicone resin treated product is typically a rubberized web, orfabric, that is very heavily impregnated with silicone. Such a treatedweb is substantially devoid of its original tactile and visualproperties, and instead has the characteristic rubbery properties of acured silicone polymer.

U.S. Pat. No. 2,673,823 teaches impregnating a polymer into theinterstices of a fabric and thus fully filling the interstices. Thispatent provides no control of the saturation of the fabric. It teachesfull saturation of the interstices of the fabric.

The prior art application of liquid or paste compositions to textilesfor purposes of saturation and/or impregnation is typically accomplishedby an immersion process. Particularly for flexible webs, includingfabric, an immersion application of a liquid or paste composition to theweb is achieved, for example, by the so-called padding process wherein afabric material is passed first through a bath and subsequently throughsqueeze rollers in the process sometimes called single-dip, single-nippadding. Alternatively, for example, the fabric can be passed betweensqueeze rollers, the bottom one of which carries the liquid or pastecomposition in a process sometimes called double-dip or double-nippadding.

Prior art treatment of webs that force a composition into the spaces ofthe web while maintaining some breathability have relied on using lowviscosity compositions or solvents to aid in the flow of thecomposition. U.S. Pat. No. 3,594,213 describes a process forimpregnating or coating fabrics with liquified compositions to create abreathable fabric. This patent imparts no energy into the composition toliquify it while forcing it into the spaces of the web. The compositionis substantially liquified before placement onto and into the web. U.S.Pat. No. 4,588,614 teaches a method for incorporating an active agentinto a porous substrate. This patent utilizes a solvent to aid in theincorporation of the active agent into the web.

Prior art apparatus for the coating of webs, including fabrics,generally deposits a coating onto the fabric at a desired thickness.Coating at a predetermined thickness can be achieved by deposition ofcoating material or by the scraping of a coating upon the fabric byknives. Flexible webs are generally urged between oppositely disposedsurfaces, one of which would be a doctoring blade or drag knife. Theblade or knife smooth the coating and maintain the thickness of thecoating to a desired thickness. For example, it is possible to apply arelatively thick silicone liquid elastomer coating to a rough web,typically of fiberglass, in order to make architectural fabric as istaught in U.S. Pat. No. 4,666,765. In this example, the drag knives areset to a thickness of about 2 to 10 mils thicker than the web thickness.This setting, depending on the coating speed, can yield a base coatthickness of approximately 3 to 12 mils thicker than the web thickness.

Various types of coatings, and various coating thicknesses, arepossible. However, a general principle of coating machinery is that thecoating material is swept, or dragged, along the surface of the fabric.No special attention is normally given to any pressured forcing of thecoating into the fabric, therein making the coating also serve as animpregnant. Of course, some coating will be urged into surface regionsof the fabric by the coating process. Generally, however, application ofhigh transversely exerted (against a fiber or web surface) forces at thelocation of the coating deposition and/or smoothing is not desired inthe prior art processes because it is the goal of the prior art coatingprocesses to leave a definite thickness of coating material upon asurface of the fabric, and not to scrape the fabric clean ofsurface-located coating material.

One prior art silicone resin composition is taught by U.S. Pat. Nos.4,472,470 and 4,500,584, and includes a vinyl terminated polysiloxane,typically one having a viscosity of up to about 2,000,000 centipoises at25° C., and a resinous organosiloxane polymer. The composition furtherincludes a platinum catalyst, and an organohydrogenpolysiloxanecrosslinking agent, and is typically liquid. Such composition is curableat temperatures ranging from room temperature to 100 C or higherdepending upon such variables as the amount of platinum catalyst presentin the composition, and the time and the temperature allowed for curing.

Such compositions may additionally include fillers, including finelydivided inorganic fillers. Silicone resin compositions that are free ofany fillers are generally transparent or translucent, whereas siliconeresin compositions containing fillers are translucent or opaquedepending upon the particular filler employed. Cured silicone resincompositions are variously more resinous, or hard, dependent upon suchvariables as the ratio of resinous copolymer to vinyl terminatedpolysiloxane, the viscosity of the polysiloxane, and the like.

Curing (including polymerization and controlled crosslinking) canencompass the same reactions. However, in the fabric finishing arts,such terms can be used to identify different phenomena. Thus,controllable and controlled curing, which is taught by the prior art,may not be the same as control of crosslinking. In the fabric finishingarts, curing is a process by which resins or plastics are set in or ontextile materials, usually by heating. Controlled crosslinking may beconsidered to be a separate chemical reaction from curing in the fabricfinishing arts. Controlled crosslinking can occur between substancesthat are already cured. Controlled crosslinking can stabilize fibers,such as cellulosic fibers through chemical reaction with certaincompounds applied thereto. Controlled crosslinking can improvemechanical factors such as wrinkle performance and can significantlyimprove and control the hand and drape of the web. Polymerization canrefer to polymer formation or polymer growth.

What is needed in the industry is a barrier fabric that is impermeableto liquids, is permeable to gases, and is impermeable to microorganisms.In addition, what is needed are methods and processes for producingfabrics with predetermined pore sizes that allow the manufacturer toproduce a fabric with a desired pore size.

SUMMARY OF THE INVENTION

The present invention includes novel barrier webs that have certaindesirable physical qualities such as water resistance, increaseddurability, improved barrier qualities and the like. The presentinvention further comprises a barrier web comprising a web that has beentreated with a curable shear thinned thixotropic polymer composition,the fabric being adapted to be substantially impermeable to liquids,permeable to gases and impermeable to microorganisms. The barrier websof the present invention are either impermeable to all microorganisms orare impermeable to microorganisms of certain sizes. The presentinvention also includes fabrics that are capable of selectively bindingcertain microorganisms, particles or molecules depending upon whatbinding partners are incorporated into the polymer before application tothe fabric.

The present invention also includes methods and machinery formanufacturing the novel barrier webs. The novel barrier webs of thepresent invention can be used to prepare a wide variety of productsincluding, but not limited to, carpets, specilized clothing, careerapparel, bioengineered surfaces for diagnostic applications, andupholstery. By practicing the present invention, fabrics, and fibers canbe manufactured with a wide variety of desired physical characteristics.

The novel fabrics of the present invention are generally flat or planar.The barrier webs can comprise fibers in the form of monofilaments,yarns, staples, or the like. The barrier webs may be a fabric which iswoven or nonwoven with fibers that can be of any desired composition.The barrier webs will generally be tensionable, but not too weak orelastomeric to be processed in accordance with the teachings of thepresent invention.

The present invention also includes barrier webs that have bioactivesurfaces. These webs can be used in a variety of ways including, but notlimited to, measurement of analytes in solution, selective filtration offluids, and the isolation of particles, such a cells, from a suspensionof particles. The present invention also contemplates assay kitscontaining the bioactive surfaces.

The fibers utilized in a porous flexible fabric employed in the practiceof the present invention can be of natural or synthetic origin. Mixturesof natural fibers and synthetic fibers can also be used. Examples ofnatural fibers include cotton, wool, silk, jute, linen, and the like.Examples of synthetic fibers include rayon, acetate, polyesters(including polyethyleneterephthalate), polyamides (including nylon),acrylics, olefins, aramids, azlons, glasses, modacrylics, novoloids,nytrils, rayons, sarans, spandex, vinal, vinyon, and the like.

The breathable barrier webs of the present invention can be used tomanufacture foul weather garments, surgical gowns, surgical scrub suits,sterilization wrappers (CSR wrap), cover gowns, isolation gowns, hamperbags, jump suit, work aprons, laboratory coats and the like. The fabricis especially suited as a barrier to prevent or control the spread ofinfectious microorganisms. The invention also includes processes formaking a woven medical fabric.

Accordingly, it is an object of the present invention to provide barrierwebs that are particularly suitable as a barrier web that issubstantially impermeable to liquids, especially aqueous liquids and ispermeable to gases.

Another object of the present invention is to provide a barrier web thatis impermeable to microorganisms including viruses, bacteria, fungi andprotozoa.

Yet another object of the present invention is to provide a barrier webthat has the additional quality of inhibiting or killing microorganisms.

Another object of the present invention is to provide a barrier web thatis suitable for use as a bandage or surgical gauze.

Another object of the present invention is to provide a barrier web thatcan be used in products for the control of incontinence such as diapers,incontinent briefs, training pants and the like.

Another object of the present invention is to provide a reusable barrierweb that can be sterilized by means other than gamma irradiation, steamautoclave or ethylene oxide.

Another object of the present invention is to provide a barrier websupport with a bioactive surface that can be used to measure analytes insolutions.

Another object of the present invention is to provide a surgical gownwith an optional web thereon that is an effective barrier against bloodor other body fluids.

Various other and further features, embodiments, and the like which areassociated with the present invention will become apparent and betterunderstood to those skilled in the art from the present descriptionconsidered in conjunction with the accompanying drawings whereinpresently preferred embodiments of the invention are illustrated by wayof example. It is to be expressly understood, however, that the drawingsand the associated accompanying portions of this specification areprovided for purposes of illustration and description only, and are notintended as limitations on the invention.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a graph plotting the rheological behavior of polymers used inthe practice of this invention.

FIG. 2 is a schematic vector diagram illustrating surface tensionforces.

FIG. 3 is a graph relating contact angle over a smooth, solid surface.

FIG. 4 illustrates diagrammatically one embodiment of a blade suitablefor use in an apparatus used in the practice of the present invention.

FIG. 5 illustrates diagrammatically a presently preferred embodiment ofan apparatus suitable for use in the practice of the present invention.

FIGS. 6a through 6g are scanning electron microscopy (SEM)photomicrographs and elemental analyses which depict various results infabrics, fibers and filaments from back scatter evaluation tests.

FIG. 7 is a top view of an incontinent brief.

FIG. 8 is a cross-section view of the incontinent brief shown in FIG. 7along section lines 8--8.

FIG. 9 is a top view of an incontinent brief.

FIG. 10 is a cross-section view of the incontinent brief shown in FIG. 9along section lines 10--10.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description includes the best presently contemplated modeof carrying out the invention. This description is made for the purposeof illustrating the general principles of the inventions and should notbe taken in a limiting sense.

The present invention includes novel webs that have certain desirablephysical qualities such as water resistance, increased durability,improved barrier qualities and the like. In one embodiment, the fabricsof the present invention are impermeable to microorganisms while, at thesame time, are permeable to gases, including water vapor, and impermableto liquids such as water, body fluids and the like. The presentinvention also includes methods and machinery for manufacturing thenovel barrier webs. The novel webs, fibers and fabrics of the presentinvention can be used to prepare a wide variety of products including,but not limited to, carpets, specilized clothing, career apparel,bioengineered surfaces for diagnostic applications, and upholstery.

The present invention relates to methods and apparatus for manufacturinga treated web and are more fully described in copending U.S. patentapplication Ser. No. 08/407,191 which is incorporated in its entirety byreference. The subject methods and apparatus involve the control ofnumerous variables, including, without limitation, web tension (bothoverall web tension as well as the web tension immediately before andafter each individual blade), angle of entry of web into each blade,blade angle in relation to horizonal reference point, blade pressureagainst moving web, angle of exit of web from each blade, web speed,number of blades, the pressure of the leading nip rolls, the pressure ofthe trailing nip rolls, static control, thickness of each blade, bevelon each blade, oven cure temperature, oven cure dwell time, bladetemperature and blade surfaces and edge conditions and blade finish.

Other variables that affect the finished product, but are not directlyrelated to the methods and apparatus, include, without limitation, thepolymer blend, the starting viscosity of the polymer composition,accelerators added to the polymer composition, additives added to thepolymer composition, the type of web used, ambient temperature,humidity, airborne contaminants, lint on web, pre-treatment of web,sub-web surface temperature, and web moisture content.

With respect to the blades, the temperature of the blade can be keptcool to keep the polymer composition from curing prematurely. This canbe accomplished by passing a coolant through or around the blade or byother means well known in the art. Alternatively, the blade could beheated by passing a heated fluid around or through the blade, if desiredto improve or alter the viscosity and rheology for the required changesin the polymer necessary to achieve a specific product.

The blade finish is also important. A hard, smooth surface of both bladeface and edges is desirable to shear thin the polymer and keep itflowing and to maximize friction or selectively create shear forcesbetween the web, the polymer, and blade(s). For some applications, theblades should preferably remain rigid in all dimensions and have minimalresonance in order to get uniform web treatment.

The apparatus has facilities for rotating the angle of each blade ±90°from the vertical. To vary the shear and placement forces of the bladeagainst the web, polymer and additives, adjustment facilities areprovided for moving the blade vertically up and down and moving theblade forward and backward horizontally. All three axis are importantfor creating the desired control which causes the encapsulated fibersand/or filaments, the additive placement and orientation on the fiberand filaments, the optional internal layer, and the controlled thicknessof the encapsulating films or internal layer. The lateral placement ofeach blade relative to the other is also important and facilities areprovided for allowing lateral movement of each blade toward and awayfrom each other. The lateral placement of each blade controls the microtension and elastic vibration of the web between the preceding roll andthe blade, thereby controlling the web after the immediate exit of theweb from the blade and controlling the Coanda Effect, as described inU.S. Pat. No. 4,539,930, so that controlled placement of the internallayer takes place.

Changing the tension of the web results in changes internally in theweb, such as the position of the internal layer of the web, as well ashow much or how little fiber encapsulation occurs, and the thickness ofthe film encapsulating the individual fibers or filaments.

At the leading edge of the blade, the web is stretched longitudinallyand the polymer is simultaneously and dynamically shear thinned, placedinto the web, and partially extracted from the web, thereby leavingencapsulated fibers and filaments and/or an internal layer. As the webpasses the leading edge of the blade, the elastic recovery forces of theweb combined with the relaxation or elastic recovery of the fibers andfilaments causes fiber encapsulation and the surface chemistrymodification (or bloom). It is believed that this occurs by the poppingapart of the individual fibers and filaments. The fibers and filamentseither pull the polymer from the interstitial spaces or the rheology ofthe polymer attracts it to the fibers and filaments or some combinationof the two. The end result is that the polymer in the interstitialspaces moves to the fibers and filaments as they move or snap apart,thereby creating encapsulated fibers and filaments. At the bottomsurface of the blade, the thickness, depth, and controlled placement ofthe internal layer is determined. A wider blade results in a thickerinternal layer of polymer. Further, the dynamics of stretch andrelaxation of the fibers provides for an even energy necessary for thethin film encapsulation of the polymer composition over the fibers.

Passing the treated web through the exit nip rolls pushes the fibers orstructural elements of the web together. The hardness of and thematerial of the exit nip rolls affects the finished web. The exit niprolls could be either two rubber rolls or two steel rolls, or one steelroll and one rubber roll, and the rubber rolls could be of differentdurometers. Further, the variation of the hardness of one or both niprolls changes the contact area or footprint between the nip rolls andthe web as the web passes therebetween. With a softer roll there is alarger contact area and the web is capable of retaining the (a) thinfilm encapsulation of the individual fibers and filaments, (b) thecontrolled placement of the internal coating, and (c) controlledplacement of the additives in (a) and (b). With a harder roll there is asmaller contact area which is appropriate for heavier webs.

Additional controllable variables include the various controls of eachblade, the nip rolls durometer, the nip release effect, the nip surfacecharacteristics, the guidance, and the pre-treatment of the substrate.Some of the controllable variables are: 1) web tension, 2) angle ofentry of fabric into the blade, 3) blade angle in reference tohorizontal position, 4) blade pressure against fabric (blade height), 5)angle of exit of fabric from blade, 6) web speed, 7) number of blades,8) initial rheology and viscosity of polymers, 9) nip pressure, 10)entry nip pressure 11) static control, 12) blade thickness and shape,13) polymers and polymer blends, 14) accelerators and inhibitors addedto polymers, 15) additives in polymers, 16) oven cure temperature, 17)oven cure dwell time, 18) substrate type, 19) ambient polymertemperature, 20) humidity, 21) degree web is deformed under lateraltension, and 22) airborne contaminants and lint on the web. Control ofthe above variables affects: (a) the thin film encapsulation of theindividual fibers and filaments, (b) the controlled placement of theinternal coating, and (c) the controlled placement of the additives in(a) and (b).

An increase in web tension causes less polymer to be applied to the web,and also, more of what is applied to be extracted from the web. Webtension occurs between the entrance pull stand and the exit pull stand.The primary tension is a result of the differential rate between thedriven entrance pull stand and the driven exit pull stand whereby theexit pull stand is driven at a rate faster than the entrance pull stand.Other factors which effect tension are (1) the blade roll diameter, (2)the vertical depth of the blade(s), (3) the durometer of the entrancepull stand roll and rubber roll of the exit pull stand, and (4) thefriction as the web passes under the blade(s). The larger the blade rolldiameter, the higher the tension of the web. If the drive rate of theweb remains constant, then increasing the depth of the blade into theweb creates a greater micro tension condition under the blade.Similarly, decreasing the depth into the web decreases the micro tensionunder the blade. The lower the durometer of the entrance pull stand rolland rubber roll of the exit pull stand, the larger the footprint orcontact area between the rolls. A larger footprint produces more surfacefriction, thereby limiting web slippage and increasing tension.Likewise, web slippage can be effected by changing the surface textureof the rolls, i.e., a smooth roll will allow greater slippage than ahighly contrasting or rough surface texture. Increasing friction, as thefabric passes under the blade(s), also produces tension. Friction is afunction of the surface area of the bottom of the blade(s). Increasingthe surface area increases the friction which increases the tension.

The entry angle of the web into the blade(s) can be varied by blade rollheight, blade roll diameter, blade angle, distance between prior bladeroll(s) and blade(s), and height of the blades. Increasing the bladeroll height and blade roll diameter increases the entry angle into theblade. Rotating the blade angle clockwise from the perpendicular, withthe web running left to right, increases the entry angle. Likewise,rotating the blade angle counter-clockwise from the perpendicular, withthe web running left to right, decreases the entry angle. Decreasing thedistance between the roll before the blade and the blade decreases theangle of entry. Increasing the downward depth of the blade(s) into theweb decreases the angle of entry into the blade(s).

The angle of the blade(s) is completely changeable and fully rotationalto 360°. The fully rotational axis provides an opportunity for more thanone blade per rotational axis. Therefore, a second blade having adifferent thickness, bevel, shape, resonance, texture, or material canbe mounted. Ideally the apparatus contains two or three blades per blademount.

The blade height or blade pressure applied against a web can be obtainedthrough the vertical positioning of the blade(s) in the blade mount. Thegreater the downward depth of the blade(s), the greater the pressure.Blade pressure against the web is also accomplished through the tensionof the web as described above.

The same line components that affect the entry angle of the web into theblade(s), also affect the exit angle of the web out of the blade. Anychanges in blade roll(s) vertical height, diameter, or distance awayfrom the blade, affects the exit angle of the web. If the angle of theblade is rotated clockwise as described above, the entry angle of theweb increases, thus decreasing the exit angle.

Web speed is proportional to the variable speed of the motor whichdrives the entrance and exit nip stands. Web speed can effect thephysics of the polymers as the web passes under the blades.

The number of blades can vary. Generally, more than one blade isrequired. The polymer is first applied onto the web prior to the firstblade. At this blade, a rolling bead of polymer can exist at theinterface of the blade and the web (entry angle) Basically, a highviscosity polymer is applied and through the process of shear thinning,the viscosity is greatly decreased, allowing the polymer to enter intothe interstitial spaces of the web. Any blade(s) after the first blade,serves to further control the polymer rheology and viscosity andcontinue the controlled placement of the polymer into the web. This isaccomplished by controllably removing excess polymer to obtain an evendistribution of polymer to any area, or a combination of the three areasof a) the thin film encapsulation of the individual fibers andfilaments, b) the controlled placement of the internal layer, and c) thecontrolled placement of the additives in a) and b).

The initial process dynamics for the rheology and viscosity of thepolymer is designed and engineered with the required attributes toachieve (a) the thin film encapsulation of the individual fibers andfilaments, (b) the controlled placement of the internal layer, and (c)the controlled placement of the additives in (a) and (b). If the polymerviscosity is high, the polymer may need to be pre-thinned by using adynamic mixer or three-roll head. The dynamic mixer or the three-rollhead can significantly reduce the viscosity and even pre-place thepolymer into a thick substrate or web to allow the blades to furthershear thin and enhance the flow and placement of the polymer.

The entrance pull stand is a driven roll proportionally driven at apredetermined rate slower than the exit pull stand. The entrance andexit pull stands are adjustable from about 100 pounds of force to 5 ormore tons of force.

The bottom rolls of both the entrance and exit pull stands havemicro-positioning capability to provide for gap adjustment andalignment. The composition of the top roll of the entrance and exit pullstands is chosen based on the durometer of the urethane or rubber. Thetop roll of the exit pull stand preferably utilizes a Teflon sleevewhich will not react with the polymers used in the process. The bottomroll of the exit pull stand is preferably chrome plated or highlypolished steel to reduce the impression into the preplaced polymer inthe web.

If desired, non-contact antistatic devices may be installed in locationswhere noticeable levels of static buildup are detected. However, thereis no evidence of adverse effects due to static buildup in the process.

Blade thickness and shape have substantial effects on the movement ofthe structural elements of the web during processing and moreimportantly, the viscoelastic flow characteristics of the polymer incontrolling (a) the thin film encapsulation of the individual fibers andfilaments, (b) the controlled placement of the internal coating, and (c)the controlled placement of the additives in (a) and (b). The bladebevel can effect the entry angle of the web and effect the sharpness ofthe leading edge of the blade. A sharper leading edge has a greaterability to push the weave or structural elements of the weblongitudinally and traversely, increasing the size of the interstitialspaces. As the web passes the leading edge of the blade, theinterstitial spaces snap back or contract to their original size. Thepolymer viscosity is reduced and the polymer is placed into the web atthe leading edge of the blade. Blade thickness and shape effects thepolymers and their selected additives and the placement thereof.Preferably, the combination of the leading edge condition and the twosurfaces (the front and the bottom) that meet at the leading edge areRMS 8 or better in grind and/or polish. This creates a precise leadingedge; the more precise the leading edge, the more the shear thinningcontrol.

There are a number of pre-qualifiers or engineered attributes ofpolymers that enhance control of flow and polymer placement in:(a) thethin film encapsulation of the individual fibers and filaments, (b) thecontrolled placement of the internal coating, and (c) the controlledplacement of the additives in (a) and (b). Blending polymers is one wayto achieve ideal flow and placement characteristics. An example of ablended polymer is where one polymer, selected for its physicalproperties, is mixed with another polymer that is selected for itsviscosity altering properties. Many tests using different polymer blendshave been done. Polymer blends vary by both chemical and physicaladhesion, durability, cure dwell time required, cure temperaturerequired, flexibility, percentage add-on required, performancerequirements, and aesthetics.

Accelerators and inhibitors which are added to polymers, generallyproduce three effects. An illustrative accelerator or inhibitor is aplatinum catalyst, which is a cure or crosslinking enhancer. The firsteffect it produces is to control the time and temperature of the web asit cures. A cure or controlled crosslinking enhancer can significantlyassist in controlling the drape and hand feel of the web. The secondeffect is to to alter the cure to allow the web to reach partial cureand continue curing after leaving an initial heat zone. This secondeffect also assists in retaining the drape and hand feel of the web. Thethird effect of inhibitors is to achieve a semi-cure for later stagingof the cure.

Additives which are added to the polymers significantly control surfacechemistry. Surface chemistry characteristics are controlled by includingadditives that have both reactive and bio-interactive capabilities. Themethod and apparatus of this invention can control the placement of theadditives on the surface of the thin film encapsulating the fibers, oneither or both surfaces of the internal layer, on either or bothsurfaces of the web, or any combination of the foregoing.

The oven cure temperature and the source and type of cure energy, arecontrolled for a number of reasons. The oven cure temperature iscontrolled to achieve the desired crosslinked state; either partial orfull. The source and type of energy can also affect the placement of thepolymer and additives. For example, by using a high degree of specificinfrared and some convection heat energy for cure, some additives can bestaged to migrate and/or bloom to the polymer surfaces.

Oven cure temperature is thermostatically controlled to a predeterminedtemperature for the web and polymers used. Machine runs of new webs arefirst tested with hand pulls to determine adhesion, cure temperature,potentials of performance values, drapability, aesthetics, etc. Theeffect on the web depends on the oven temperature, dwell time and curingrate of the polymer. Webs may expand slightly from the heat.

Oven cure dwell time is the duration of the web in the oven. Oven curedwell time is determined by the speed of the oven's conveyor andphysical length of the oven. If the dwell time and temperature for aparticular web is at maximum, then the oven conveyor speed would dictatethe speed of the entire process line or the length of the oven wouldhave to be extended in order to increase the dwell time to assure properfinal curing of the web.

The physical construction and chemistry of the web is critical. Theamount of control over the rheology of the polymer and the tension onthe web are dependent on the physical construction and chemistry. Theweb selected must have physical characteristics that are compatible withthe flow characteristics of the polymer.

The ambient polymer temperature refers to the starting or first stagingpoint to controlling the viscosity and rheology. The process head cancontrol the ambient polymer temperature through temperature controlledpolymer delivery and controlled blade temperatures.

Humidity can sometimes inhibit or accelerate curing of the polymer.Therefore, humidity needs to be monitored and, in some conditions,controlled.

The degree the web is deformed under lateral tension is controllable bythe choice of the physical construct of the web, the blade angle, theblade leading edge condition, and the micro and macro tension of theweb.

Airborne contaminants and lint on the web can affect primability and cancreate pin holes in the polymer. Therefore, airborne contaminants andlint on the web need to be controlled to reduce or eliminate pin holesor uncontrolled primability.

In view of the fact that between the shear thinning stations and theoven, the polymer composition may begin to set or partially cure, it maybe desirable to overshear so that by the time the web gets to the curingoven, it will be at the point where it is desired that the cure occur.This over shear effect is a matter of controlling certain variables,including the force of the blades against the moving web, as well as thetension and speed of the web.

By having a number of shear thinning blades, you create a multiple shearthinning effect, which changes the final construct of the polymer andthe (a) thin film encapsulation of the individual fibers and filaments,(b) controlled placement of the internal coating, and (c) controlledplacement of the additives in (a) and (b). It is understood that thefirst shear thinning causes viscoelastic deformation of the polymercomposition which, due to its memory, tends to return to a certainlevel. With each multiple shear thinning, the level to which the polymerstarts at that shear point and returns is changed. This is calledthixotropic looping or plateauing (See FIG. 1).

Definitions

As employed herein, the term "adhesiveness" refers to the capacity tobind other solids by both chemical and physical means

The term "analyte," as used herein, refers to any molecule, molecularcomplex or particles in a fluid that is measurable or can be isolatedusing the barrier webs of the present invention. This term is also meantto include large particles such as cells and microorganisms, includingviruses, bacteria, protozoa and fungi or components of themicroorganisms such as proteins, peptides, glycoproteins, lipids,ribonucleic acid or sugars. The term "analyte" also includes latexparticles or other particulate matter.

The phrase "antistatic character," as used herein, refers to thecapacity to reduce the generation of charge, increase the rate of chargedissipation, inhibit the production of charge, or some combination ofthe foregoing.

The term "bioactive surfaces," as used herein, includes, but is notlimited to, the incorporation of antibodies, antigens, enzymes, or otherbioactive molecules into the polymer to be applied to a fabric or othersurface thereby forming a surface with the bioactive molecule attachedthereto.

The phrase "biocidal activity," as used herein, refers to the capacityof a compound to kill pathogenic and/or non-pathogenic microorganisms,and prevent or inhibit the action or growth of microorganisms includingviruses and bacteria. Biocidal activity can be measured by applying TestMethods 100-1993, 147-1993, and 174-1993 of the Technical Manual of theAmerican Association of Textile Chemist and Colorist (AATCC), DowCorning Corporate Test Method 0923, and the Kirby-Bauer StandardAntimicrobial Susceptibility Test as described in the Manual of ClinicalMicrobiology, Fourth Edition, all of which are incorporated herein byreference.

As employed herein, the term "biocide," as used herein, refers to anyphysical or chemical agent capable of combating pathogenic andnon-pathogenic microorganisms, including bacteria and viruses.

As employed herein, the phrase "biological activity" refers to thefunctionality, reactivity, and specificity of compounds that are derivedfrom biological systems or those compounds that are reactive to them, orother compounds that mimic the functionality, reactivity, andspecificity of these compounds. Examples of suitable biologically activecompounds include enzymes, antibodies, antigens and proteins.

The term "bodily fluid," as used herein, includes, but is not limitedto, saliva, gingival secretions, cerebrospinal fluid, gastrointestinalfluid, mucous, urogenital secretions, synovial fluid, blood, serum,plasma, urine, cystic fluid, lymph fluid, ascites, pleural effusion,interstitial fluid, intracellular fluid, ocular fluids, seminal fluid,mammary secretions, and vitreal fluid, and nasal secretions.

The term "breathability," as used herein, refers to gas permeabilitysuch as the moisture vapor transmission of a material as measured byASTM E96 and the specifically developed modified "Bellow's Test"described in subsequent sections.

The term "coating" as used herein, refers to a generally continuous filmor layer formed by a material over or on a surface.

As employed herein, the phrase "color fastness" refers to the capacityof a fabric to resist fading during a period of normal wear and multiplewashings and dry cleaning. Color fastness is determined under conditionsof accelerated weathering.

With respect to the polymer compositions used in this invention, theterm "controlled placement" or "placement" refers to the penetration ofsuch polymer compositions into a porous web, to the distribution of suchcomposition in a controlled manner through such web, and to theresultant, at least partial envelopment of at least a portion of thefibers of such web by such composition in accordance with the presentinvention, or to the formation of an internal layer, or both.

The term "curing", or "cure", as used herein, refers to a change instate, condition, and/or structure in a material, such as a curablepolymer composition that is usually, but not necessarily, induced by atleast one applied variable, such as time, temperature, radiation,presence and quantity in such material of a curing catalyst or curingaccelerator, or the like. The term "curing" or "cured" covers partial aswell as complete curing. In the occurrence of curing in any case, suchas the curing of such a polymer composition that has been selectivelyplaced into a porous flexible substrate or web, the components of such acomposition may experience occurrence of one or more of complete orpartial (a) polymerization, (b) cross-linking, or (c) other reaction,depending upon the nature of the composition being cured, applicationvariables, and presumably other factors. It is to be understood that thepresent invention includes polymers that are not cured after applicationor are only partially cured after application.

As employed herein, the term "durability" refers to the capacity of afabric to retain its physical integrity and appearance during a periodof normal wear and multiple washings and dry cleaning.

The term "elastomeric" as used herein refers to the ability of a curedpolymer treated web to stretch and return to its original state.

The phrase "electrical conductivity," as used herein refers to thecapacity to conduct electrical current.

The phrase "electromagnetic radiation absorptivity," as used herein,refers to the absorption of radiation of wavelengths from within theelectromagnetic spectrum.

The phrase "electromagnetic shielding capacity," as used herein, refersto the capacity to reflect, absorb, or block electromagnetic radiation.

The term "envelop" or "encapsulate" as used interchangeably herein,refers to the partial or complete surrounding, encasement, or enclosingby a discrete layer, film, coating, or the like, of exposed surfaceportions of at least some individual fiber or lining of a cell or porewall of a porous web. Such a layer can sometimes be contiguous orintegral with other portions of the same enveloping material whichbecomes deposited on internal areas of a web which are adjacent to suchenveloping layer, enveloped fiber, lined cell or pore wall, or the like.The thickness of the enveloping layer is generally in the range of 0.01to 50 microns, and preferably in the range of about 0.1 to 20 microns.

The term "fiber", as used herein, refers to a long, pliable, cohesive,natural or man-made (synthetic) threadlike object, such as amonofilament, staple, filament, or the like. A fiber usable in thisinvention preferably has a length at least 100 times its diameter orwidth. Fibers can be regarded as being in the form of units which can beformed by known techniques into yarns or the like. Fibers can be formedby known techniques into woven or non-woven webs (especially fabrics)including weaving, knitting, braiding, felting, twisting, matting,needling, pressing, and the like. Preferably, fibers, such as those usedfor spinning, as into a yarn, or the like, have a length of at leastabout 5 mm. Fibers such as those derived from cellulosics of the typeproduced in paper manufacture can be used in combination with longerfibers as above indicated, as those skilled in the art will readilyappreciate.

The term "filament" as used herein refers to a fiber of indefinitelength.

The term "filled" as used herein in relation to interstices, orinterstitial spaces, or open cells, and to the amount of polymercomposition therein in a given web, substrate, or the fibers in such webor substrate, designates the presence of such composition therein. Whena given interstitial space or open cell is totally taken up by suchcomposition, it is "completely filled" or "plugged". The term "filled"also refers to an interstitial space having a film or layer of polymercomposition over or through it so that it is closed even though theentire thickness of the interstitial space is not completely filled orplugged.

Measurements of the degree of envelopment, interstitial fillage,plugging, or the like in an internal coating are conveniently made bymicroscopy, or preferably by conventional scanning electron microscopy(SEM) techniques. Because of the nature of such measuring by SEM forpurposes of the present invention, "a completely filled" interstitialspace or open cell can be regarded as a "plugged" interstitial space oropen cell.

The term "flattening agent," as used herein, refers to a compound thatdulls the finish on glossy fabrics.

The term "flow" or "flowability" as used herein means the altering ofthe rheology of a material by the application of energy to a suitablematerial so as to allow the flowing of the material to form: (a) a thinfilm of a polymer composition encapsulating the structural elements(i.e., the fibers or filaments) making up the web leaving at least someof the interstitial spaces open; (b) an internal layer of a polymercomposition between the upper and lower surfaces of the web; or (c) somecombination of the foregoing.

The phrase "fluid resistance," as used herein, refers to the ability ofa material to resist the penetration of fluids. Fluid resistance ismeasured by the Rain test, Suter test, and hydrostatic resistancemeasurements, discussed in the "Examples" section and incorporatedherein by reference. Fluid resistance, for purposes of the presentinvention, is the result of two conditions. First, the surface of theweb has the potential for increased fluid resistance due to the choiceof the polymer and also the choice of additives and/or modifiers tocontrol surface energies. Second, the external fluid resistant or fluidproof properties can be altered by controlling the effective pore sizeof the web. Additives and/or modifiers can serve to increase or decreasethe effective pore size by controlling the viscosity and rheologyachieved through the processing of polymer in the machine. In addition,the bimodal distributions of pore sizes found in a woven fabric arecontrolled by the processing. The larger pore sizes are supplied by thespaces between yarns while smaller pores reflect the yarn structure andthe polymer composition pore size.

As employed herein, the term "functional" refers to a particularperformance attribute such as biocidal activity, therapeutic activity,ion-exchange capacity, biological activity, biological interactivecapacity to bind compounds, surface chemistry activity, electromagneticradiation absorptivity, adhesiveness, hand, durability, colorfastedness, light reflectivity, fluid resistance, waterproofness,breathability, mildew resistivity, rot resistivity, stain resistivity,electrical conductivity, thermal conductivity, antistatic character,processability, rheological character, electromagnetic shieldingcapacity, and radio frequency shielding capacity.

The term "hand" refers to the tactile feel and drapability or quality ofa fabric as perceived by the human hand.

With respect to the fluorochemical liquid dispersions (or solutions)which can optionally be used for web pretreatment, the term"impregnation" refers to the penetration of such dispersions into aporous web, and to the distribution of such dispersions in a preferably,substantially uniform and controlled manner in such web, particularly asregards the surface portions of the individual web component structuralelements and fibers.

The terms "internal coating" or "internal layer" can be usedinterchangeably. As used herein, the terms refer to a region generallyspaced from the outer surfaces of the web which is substantiallycontinuously filled by the combination of the polymer controllablyplaced therein and the fibers and filaments of the web in the specifiedregion. Such coating or layer envelopes, and/or surrounds, and/orencapsulates individual fibers, or lines cell or pore walls of theporous web or substrate, in the specified region. The internal layer isnot necessarily flat but may undulate or meander through the web,occasionally even touching one or both surfaces of the web. Generally,the internal layer is exposed on both sides of a web as part of themulti complex structure of a woven and non-woven web. The thickness ofthe internal layer is generally in the range of 0.01 to 50 microns, andpreferably in the range of about 0.1 to 20 microns.

As used herein, the phrase "ion-exchange capacity" refers to thecapacity to exchange mobile hydrated ions of a solid, equivalent forequivalent, for ions of like charge in solution.

The phrase "light reflectivity," as used herein, refers to the capacityto reflect light from the visual region of the electromagnetic spectrum

The phrase "mildew resistance," as used herein, refers to the capacityto either kill or prevent or inhibit the growth of mildew. Mildewresistance can be quantified by Test Method 30-1993 of the TechnicalManual of the American Association of Textile Chemist and Colorist(AATCC), incorporated herein by reference.

The term "modifiers," "agents," or "additives," used interchangeablyherein, refers to materials and compounds that impart or alter specificphysical or chemical characteristics with respect to the articlesproduced therefrom. These physical or chemical characteristics aretypically functional properties. The modifiers may also alter or impartfunctional properties to the thixotropic material. Examples of modifierssuitable for use in the practice of the present invention includebiocides, therapeutic agents, nutrients, adhesive agents,humidity-controlling agents, water repellents, ion-exchange agents,light-reflective agents, dyes and pigments, mildew-resistance agents,conductive agents, proteins, hand-altering agents, blood repellents,flexibility-inducing agents, light fastness-inducing agents,rot-resistant agents, stain-resistant agents, grease-resistant agents,ultraviolet-absorbing agents, fillers, flattening agents, electricalconductive agents, thermal conductive agents, flame retardants,antistatic agents, electromagnetic shielding agents, and radio frequencyshielding agents. Examples of suitable nutrients which can be employedin the practice of the present invention include cell growth nutrients.

The term "particle," as used herein, refers to any particulate matterincluding, but not limited to, microorganisms including viruses,bacteria, protozoa, or fungi, cells and cell fragments such asplatelets, as well as inanimate particles such as latex particles. Theterm "particle," as used herein, can also mean molecules.

The term "polymer", or "polymeric" as used herein, refers to monomersand oligomers as well as polymers and polymeric compositions, andmixtures thereof, to the extent that such compositions and mixtures arecurable and shear thinnable.

As employed herein, the term "processability" refers to the nature of amaterial with respect to its response to various processing methods andprocess parameters. Processing agents contemplated for use in thepractice of the present invention could also include cross-linkinhibitors that either delay the onset of cure or slow the cure rate ofthe curable, thixotropic material, and thixotropy inducing orrheological agents that, for example, alter the viscosity of the curablematerial, and the like.

The phrase "radio frequency shielding capacity," as used herein, refersto the capacity to reflect, absorb, or block radio frequency waves.

As employed herein, the phrase "rheological character" refers tomaterial attributes such as flow, viscosity, elasticity, and the like.

As employed herein, the phrase "rot resistance" refers to the capacityto prevent or inhibit the decay of naturally-derived materials.

The term "shear thinning," in its broadest sense, means the lowering ofthe viscosity of a material by the application of energy thereto.

The phrase "stain resistance," as used herein, refers to the ability ofa material to resist coloring by a solution or a dispersion of colorant.Waterborne stain resistance refers to the ability to resist coloring bya waterborne stain.

As employed herein, the quantity meant by the term "sufficient" willdepend on the nature of the energy source, the porous substrate, thecurable, thixotropic material, the additives and/or modifiers used, andthe desired functional properties of the article produced therefrom. Adescription of the method and several examples are provided to provideenough guidance to one of skill in the art to determine the amount ofenergy required to practice this invention.

As employed herein, the phrase, "surface chemistry activity" refers tothe composition, reactivity, and positioning of chemical moities on thesurfaces of the porous substrate. As contemplated for use in thepractice of the present invention, modifiers that alter the surfacechemistry of the resulting article include fluorochemical compounds,proteins, and any other modifier compound that can be selectivelypositioned at the various surfaces within the porous substrate.

The phrase "therapeutic activity," as employed herein, refers to thecapacity to treat, cure, or prevent a disease or condition. As employedherein, the term "therapeutic agents" refers to compound(s) that areeffective at treating, curing, or preventing a disease or condition.

The phrase "thermal conductivity," as used herein refers to the capacityto conduct heat.

The word "thixotropy" refers herein to liquid flow behavior in which theviscosity of a liquid is reduced by shear agitation or stirring so as toallow the placement of the liquid flow to form: (a) a thin film of apolymer composition encapsulating the structural elements (i.e., thefibers or filaments) making up the web leaving at least some of theinterstitial spaces open; (b) an internal layer of a polymer compositionbetween the upper and lower surfaces of the web; or (c) some combinationof the foregoing. It is theorized to be caused by the breakdown of someloosely knit structure in the starting liquid that is built up during aperiod of rest (storage) and that is broken down during a period ofsuitable applied stress.

As employed herein, the phrase "waterproofness" refers to the wettingcharacteristic of a material with respect to water. Waterproofness ismeasured using the Mullen Test, Federal Standard 191, method 5 512,incorporated herein by reference.

The term "web" as used herein is intended to include fabrics and refersto a sheet-like structure (woven or non-woven) comprised of fibers orstructural elements. Included with the fibers can be non-fibrouselements, such as particulate fillers, binders, dyes, sizes and the likein amounts that do not substantially affect the porosity or flexibilityof the web. While preferably, at least 50 weight percent of a webtreated in accordance with the present invention is fibers, morepreferred webs have at least about 85 weight percent of their structureas fiber. It is presently preferred that webs be untreated with anysizing agent, coating, or the like, except as taught herein. The web maycomprise a laminated film or fabric and a woven or non-woven poroussubstrate. The web may also be a composite film or a film laminated to aporous substrate or a double layer.

The term "webs" includes flexible and non-flexible porous webs. Websusable in the practice of this invention can be classified into twogeneral types:

(A) Fibrous webs; and

(B) Substrates having open cells or pores, such as foams.

A porous, flexible fibrous web is comprised of a plurality of associatedor interengaged fibers or structural elements having interstices orinterstitial spaces defined therebetween. Preferred fibrous webs caninclude woven or non-woven fabrics. Other substrates include, but arenot limited to, a matrix having open cells or pores therein such asfoams or synthetic leathers.

The term "wound dressing" as used herein means any web or fabric that isused to cover a wound. This term includes bandages, surgical gauze,surgical dressings, burn dressings and the like.

The term "yarn" as used herein refers to a continuous strand comprisedof a multiplicity of fibers, filaments, or the like in a bundled form,such as may be suitable for knitting, weaving or otherwise used to forma fabric. Yarn can be made from a number of fibers that are twistedtogether (spun yarn) or a number of filaments that are laid togetherwithout twist (a zero-twist yarn).

A flexible porous web used as a starting material in the presentinvention is generally and typically, essentially planar or flat and hasgenerally opposed, parallel facing surfaces. Such a web is athree-dimensional structure comprised of a plurality of fibers withinterstices therebetween or a matrix having open cells or pores therein.The matrix can be comprised of polymeric solids including fibrous andnon-fibrous elements.

Three principal classes of substrates having open pores or cells may beutilized in the present invention: leathers (including natural leathers,and man-made or synthetic leathers), foamed plastic sheets (or films)having open cells, and filtration membranes.

Foamed plastic sheet or film substrates are produced either bycompounding a foaming agent additive with resin or by injecting air or avolatile fluid into the still liquid polymer while it is being processedinto a sheet or film. A foamed substrate has an internal structurecharacterized by a network of gas spaces, or cells, that make suchfoamed substrate less dense than the solid polymer. The foamed sheets orfilm substrates used as starting materials in the practice of thisinvention are flexible, open-celled structures.

Natural leathers suitable for use in this invention are typically splithides. Synthetic leathers have wide variations in composition (orstructure) and properties, but they look like leather in the goods inwhich they are used. For purposes of technological description,synthetic leathers can be divided into two general categories: coatedfabrics and poromerics.

Synthetic leathers which are poromerics are manufactured so as toresemble leather closely in breathability and moisture vaporpermeability, as well as in workability, machinability, and otherproperties. The barrier and permeability properties normally areobtained by manufacturing a controlled microporous (open celled)structure.

Synthetic leathers which are coated fabrics, like poromerics, have abalance of physical properties and economic considerations. Usually thecoating is either vinyl or urethane. Vinyl coatings can be either solidor expanded vinyl which has internal air bubbles which are usually aclosed-cell type of foam. Because such structures usually have anon-porous exterior or front surface or face, such structures displaypoor breathability and moisture vapor transmission. However, since theinterior or back surface or face is porous, such materials can be usedin the practice of this invention by applying the curable, thixotropicmaterial and one or more modifier to the back face thereof.

Filtration membranes contemplated for use in the practice of the presentinvention include microporous membranes, ultrafiltration membranes,asymmetric membranes, and the like. Suitable membrane materials includepolysulfone, polyamide, polyimide, nitrocellulose, cellulose acetate,nylon and derivatives thereof.

Other porous webs suitable for use in the practice of the presentinvention include fibers, woven and non-woven fabrics derived fromnatural or synthetic fibers, papers, and the like. Examples of papersare cellulose-based and glass fiber papers.

The fibers utilized in a porous flexible web treated by the methods andapparatus of the present invention can be of natural or syntheticorigin. Mixtures of natural fibers and synthetic fibers can also beused. Examples of natural fibers include cotton, wool, silk, jute,linen, and the like. Examples of synthetic fibers include acetate,polyesters (including polyethyleneterephthalate), polyamides (includingnylon), acrylics, olefins, aramids, azlons, glasses, modacrylics,novoloids, nytrils, rayons, sarans, spandex, vinal, vinyon, regeneratedcellulose, cellulose acetates, and the like. Blends of natural andsynthetic fibers can also be used.

A porous web or fabric is preferably untreated or scoured before beingtreated in accordance with the present invention. Preferably a web canbe preliminarily treated, preferably saturated, for example, by padding,to substantially uniformly impregnate the web with a fluorochemical.Typically, and preferably, the treating composition comprises adispersion of fluorochemical in a liquid carrier. The liquid carrier ispreferably aqueous and can be driven off with heat after application.The treating composition has a low viscosity, typically comparable tothe viscosity of water or less. After such a treatment, it is presentlypreferred that the resulting treated web exhibits a contact angle withwater measured on an outer surface of the treated web that is greaterthan about 90 degrees. The treated web preferably containsfluorochemical substantially uniformly distributed therethrough. Thus,the fluorochemical is believed to be located primarily on and in theindividual fibers, cells or pores with the web interstices or open cellsbeing substantially free of fluorochemical.

A presently preferred concentration of fluorochemical in a treatmentcomposition is typically in the range of about 1 to about 10%fluorochemical by weight of the total treating composition weight, andmore preferably is about 2.5% of an aqueous treating dispersion. Webweight add-ons of the fluorochemical can vary depending upon suchfactors as the particular web treated, the polymer composition to beutilized in the next step of the treatment process of this invention,the ultimate intended use and properties of the treated web of thisinvention, and the like. The fluorochemical weight add-on is typicallyin the range of about 0.01 to about 5% of the weight of the untreatedweb. After fluorochemical controlled placement, the web is preferablysqueezed to remove excess fluorochemical composition after which the webis heated or otherwise dried to evaporate carrier liquid and therebyalso accomplish fluorochemical insolubilization or sintering, ifpermitted or possible with the particular composition used.

The fluorochemical treated web thereafter has a predetermined amount ofa curable polymer composition controllably placed within the web by themethods and apparatus of this invention, to form a web whose fibers,cells or pores are at least partially enveloped or lined with thecurable polymer composition, whose web outer surfaces are substantiallyfree of the curable polymer, whose web interstices or open cells are notcompletely filled with the curable polymer and which may also contain aninternal layer of polymer. The curable polymer composition utilizedpreferably exhibits a starting viscosity greater than 1,000 centipoiseand less than 2,000,000 centipoise at rest at 25° C. at a shear rate of10 reciprocal seconds.

The fluorochemical residue that remains after web treatment may not beexactly evenly distributed throughout the web, but may be present in theweb in certain discontinuities. For example, these discontinuities maybe randomly distributed in small areas upon an individual fiber'ssurface. However, the quantity and distribution of fluorochemicalthrough a web is believed to be largely controllable. Some portions ofthe fluorochemical may become dislodged from the web and migrate throughthe polymer due to the forces incurred by the shear thinning andcontrolled placement of the polymer.

The curable polymer composition is believed to be typically polymeric,(usually a mixture of co-curable polymers and oligomers), and to includea catalyst to promote the cure. The polymers that can be used in thepresent invention may be monomers or partially polymerized polymerscommonly known as oligomers, or completely polymerized polymers. Thepolymer may be curable, partially curable or not curable depending uponthe desired physical characteristics of the final product. The polymercomposition can include conventional additives.

While silicone is a preferred composition, other polymer compositionsinclude polyurethanes, fluorosilicones, silicone-modified polyurethanes,acrylics, polytetrafluoroethylene-containing materials, and the like,either alone or in combination with silicones.

It is to be understood that the depth of polymer placement into a webcan be controlled by the methods herein described to provide selectiveplacement of the polymer within the web. Any additives and/or modifiersmixed into the polymer blend will likewise be selectively placed alongwith the polymer composition. The web is thereafter optionally cured toconvert the curable composition into a solid elastomeric polymer.

The polymer composition is theorized to be caused to flow and distributeitself over fibers, cells or pores in a web under the influence of theprocessing conditions and apparatus provided by this invention. Thisflow and distribution is further theorized to be facilitated andpromoted by the presence of a fluorochemical which has beenpreliminarily impregnated into a web, as taught herein. The amount offluorochemical or fluorochemical residue in a web is believed toinfluence the amount, and the locations, where the polymer will collectand deposit, and produce encapsulated fibers and/or an internal layer inthe web. However, there is no intent to be bound herein by theory.

Some portion of the residue of fluorochemical resulting from apreliminary web saturating operation is theorized to be present upon atreated fiber's surfaces after envelopment of fibers, cells or pores bythe polymer has been achieved during the formation of the encapsulatingfiber and/or the internal layer by the practice of this invention. Thisis believed to be demonstrated by the fact that a web treated by thisinvention still exhibits an enhanced water and oil repellency, such asis typical of fluorochemicals in porous webs. It is therefore believedthat the fluorochemicals are affecting the adherence of the polymer as athin film enveloping layer about the treated fibers, cells or pores aswell as facilitating polymer pressurized flow within and about theinterstices or open cells of the web being treated so that the polymercan assume its position enveloping the fibers or lining the cells orpores of the substrate.

In those fabrics that are pre-treated with fluorochemicals, the exactinterrelationship between the polymer film and the impregnatedfluorochemical is presently difficult, or perhaps impossible, toquantify because of the variables involved and because transparentpolymer is difficult to observe by optical microscopy. It can betheorized that perhaps the polymer and the fluorochemical each tend toproduce discontinuous films upon the fiber surface, and that such filmsare discontinuous in a complementary manner. It may alternatively betheorized that perhaps the polymer film is contiguous, or substantiallyso, relative to fluorochemical molecules on a fiber surface, and thatthe layer of polymer on a fiber surface is so thin that any dislodgementof the fluorochemical may release the fluorochemical into the polymerfilm thereby allowing the fluorine to orient or project through the filmwith the required cure temperature of the polymer, reactivating thewater surface contact angle so that the water repellent properties ofthe fluorochemical affect the finished product. However, regardless ofphysical or chemical explanation, the combination of polymer film andfluorochemical results in a fiber envelopment or cell or pore walllining and the formation of encapsulated fibers and/or an internal layerof polymer in a web when this invention is practiced. After curing, thepolymer is permanently fixed material.

By using the methods of this invention, one can achieve a controlledplacement of one or more additives and/or modifiers on and within the(a) thin film encapsulation of the individual fibers and filaments, (b)the controlled placement of the internal coating, and (c) somecombination of (a) and (b).

A curable polymer optionally mixed with one or more additives and/ormodifiers is applied onto and into a tensioned web using compressive andshear forces. The extent of orienting additives and/or modifiers on andwithin the fiber envelopment and the cell or pore wall lining isbelieved to be regulatable. Regulating such orientation is accomplishedby controlling the factors discussed previously, the selection andamount of fluorochemical, the type of polymer and additives (and/ormodifiers) used, and the amount of compressive and shear forces employedat a given temperature. Such control ensures that fiber envelopment isachieved while the interstices and/or open cells of the web are notcompletely filled with such polymer in the region of the internal layerand that the outer opposed surfaces of the web are substantiallycompletely free of polymer coating or residue. After such a procedure,the curable polymer is cured.

The curable polymer is optionally mixed with one or more additivesand/or modifiers and then applied onto the surface of the web. Then theweb, while tensioned, is passed over and against shearing means orthrough a compression zone, such as between rollers or against a shearknife. Thus, transversely applied shear force and compressive pressureis applied to the web. The combination of tension, shearing forces, andweb speed is sufficient to cause the polymer composition to move intothe web and out from the interstices or open cells around the webfibers, cells, or pores being enveloped. The result is that at leastsome of the interstices and/or open cells are unfilled in regions of theweb outside of the region occupied by the internal coating or internallayer, and are preferably substantially free of polymer. Excess polymeris removed by the surface wiping action of the shearing means. Thecurable polymer enveloping the fibers is thereafter cured.

The desired penetration of, and distribution and placement of polymerand additives and/or modifier(s) in a web is believed to be achieved bylocalized pressuring forces exerted on a web surface which aresufficiently high to cause the viscosity of a polymer composition to belocally reduced, thereby permitting such polymer to flow under suchpressuring and to be controllably placed within the web and to envelopeits fibers or line the cell or pore walls thereof. To aid in thisprocess, the web is preferably at least slightly distorted by tensioningor stretching, while being somewhat transversely compressed at thelocation of the controlled placement. This distortion is believed tofacilitate the entrance of the polymer composition into the web and theorientation of one or more additives and/or modifiers onto and into theweb. When the compression and tension are released, the polymercomposition is believed to be squeezed or compressed within and throughthe interstitial spaces, or open cell spaces, of the treated web.

If, for example, too much polymer is present in the finished product,then either or both the tension and shear force can be increased, andvice versa for too little polymer. If flow is not adequate upon thefibers, producing incomplete fiber envelopment, then the viscosity ofthe polymer composition can be reduced by increasing the pressuresand/or temperatures employed for the controlled placement thereof.Alternatively, if the viscosity is too low, then the pressure and/ortemperature can be decreased. If the polymer composition is resistant tobeing positioned or placed in a desired location in a desired amount ina given web at various viscosities and/or pressures, then the level offluorochemical pretreatment of the web can be increased, or decreased,as the case may be. The above factors also influence the placement ofadditives and/or modifiers when the additives and/or modifiers are mixedinto the polymer composition.

Some additives and/or modifiers, due to their physical and chemicalproperties, cannot be incorporated on and within a web by pre-treatingthe web or by mixing the additives and/or modifiers into the polymercomposition. Such additives and/or modifiers can be topically applied tothe web after the pressured, shear thinning stage described above, butbefore curing. Once topically applied, the additives and/or modifiersare forced into the web by passing through the exit nip rolls. Theadditives and/or modifiers will adhere to the polymer composition thatforms encapsulated fibers, an internal layer, or some combination of theabove. Some additives and/or modifiers may even adhere to the structuralelements of the web.

As indicated above, the activity transpiring at a final step in thepractice of this invention is generically referred to as curing.Conventional curing conditions known in the prior art for curing polymercompositions are generally suitable for use in the practice of thisinvention. Thus, temperatures in the range of about 250° F. to about350° F. are used and times in the range of about 30 seconds to about 1minute can be used, although longer and shorter curing times andtemperatures may be used, if desired, when thermal curing is practiced.Radiation curing, as with an electron beam or ultraviolet light can alsobe used. However, using platinum catalysts to accelerate the cure whileusing lower temperatures and shorter cure times is preferable.

Since either filled, plugged, almost filled interstices, or open cellsin the region of an internal layer remain transmissive of air in curedwebs made by this invention, the webs are characteristically airpermeable or breathable.

Sample webs or fabrics that are beneficially treated, fiber envelopedand internally coated in accordance with the invention include nylon,cotton, rayon and acrylic fabrics, as well as fabrics that are blends offiber types. Sample nylon fabrics include lime ice, hot coral, raspberrypulp, and diva blue Tactel® (registered trademark of ICI Americas, Inc.)fabrics available from agent Arthur Kahn, Inc. Sample cotton fabricsinclude Intrepid® cotton cornsilk, sagebrush cotton, and light bluecotton fabrics available also from Arthur Kahn, Inc. Non-woven,monofilamentous, fabrics such as TYVEK® (registered trademark of E.I.duPont de Nemours Co., Inc.) and the like are also employable.

As indicated above, a web is preferably pretreated and impregnated witha fluorochemical prior to being treated with a polymer composition astaught herein. The fluorochemical impregnation is preferablyaccomplished by first saturating a web with a liquid composition whichincorporates the fluorochemical, and then, thereafter, removing theexcess liquid composition and residual carrier fluid by draining,compression, drying, or some combination thereof from the treated web.

It is now believed that any fluorochemical known in the art for use inweb, particularly fabric treatment in order to achieve water repellency,soil repellency, grease repellency, or the like, can be used forpurposes of practicing the present invention. It is believed that atypical fluorochemical of the type used for web treatment can becharacterized as a compound having one or more highly fluorinatedportions, each portion being a fluoroaliphatic radical or the like, thatis (or are) functionally associated with at least one generallynon-fluorinated organic portion. Such organic portion can be part of apolymer, part of a reactive monomer, a moiety with a reactable siteadapted to react with a binder, or the like. Such a compound istypically applied to a fabric or other web as a suspension or solutionin either aqueous or non-aqueous media. Such application may beconventionally carried out in combination with a non-fluorine orfluorine containing resin or binder material for the purpose ofproviding improved durability as regards such factors as laundering, drycleaning, and the like.

Fluorochemicals are sometimes known in the art as durable waterrepellent (DWR) chemicals, although such materials are typicallybelieved to be not particularly durable and to have a tendency to washout from a fabric treated therewith. In contrast, fiber enveloped websof this invention which have been pretreated with a fluorochemicaldisplay excellent durability and washability characteristics. Indeed,the combination of fluorochemical pretreatment and silicone polymerfiber envelopment such as provided by the present invention appears toprovide synergistic property enhancement because the effects orproperties obtained appear to be better than can be obtained than byusing either the fluorochemical or the silicone polymer alone for webtreatment.

Exemplary water repellent fluorochemical compositions include thecompositions sold under the name Milease® by ICI Americas Inc. with thetype designations F-14N, F-34, F-31X, F-53. Those compositions with the"F" prefix indicate that they contain a fluorochemical as the principalactive ingredient. More particularly, Milease® F-14 fluorochemical, forexample, is said to contain approximately 18 percent perfluoroacrylatecopolymer, 10 percent ethylene glycol (CAS 107-21-1) and 7 percentacetone (CAS 67-64-1) dispersed and dissolved in 65 percent water.Milease® F-31X is said to be a dispersion of a combination offluorinated resin, acetone, and water.

Still another suitable class of water repellent chemicals is thePhobotex® chemicals of Ciba/Geigy identified as Phototex® FC104, FC461,FC731, FC208 and FC232 which are each believed to be suitable for use,typically in approximately a 5 percent concentration, in saturating aweb for use in the invention. These and many other water repellentfluorochemicals are believed to be capable of creating a surface contactangle with water of greater than about 90 degrees when saturated into aweb and to be suitable for use in the practice of this invention.

Another group of useful water repellent fluorochemicals is theTEFLON®-based soil and stain repellents of E.I. dupont de Nemours & Co.Inc., 1007 Market Street, Wilmington, Del. 19898. Suitable TEFLON® typesfor use in the practice of this invention include TEFLON® G. NPA, SKF,UP, UPH, PPR, N. and MLV. The active water repellent chemical of eachcomposition is believed to be a fluorochemical in polymeric form that issuitable for dispersion in water, particularly in combination with acationic surfactant as a dispersant. These dispersions are dilutable inall proportions with water at room temperature. One preferred class offluorochemical treating compositions useful in the practice of thisinvention comprises about 1 to about 10 weight percent, more preferablyabout 5 weight percent of one of the above indicated TEFLON®-type waterrepellent fluorochemcials in water.

Another major group of suitable water repellent fluorochemicalcompositions useful in the practice of the invention is commerciallyavailable under the designation ZEPEL® rain and stain repellentchemicals of E.I. dupont de Nemours & Co. Inc., such as ZEPEL® waterrepellent chemicals types B. D, K, RN, RC, OR, HT, 6700 and 7040. Eachis believed to be a fluorochemical in polymeric form that is dispersiblein all proportions at room temperature. The dispersants ZEPEL® B. D, K,and RN are believed to be cationic, while the dispersant ZEPEL® RC isbelieved to be nonionic.

As an exemplary composition, ZEPEL® 6700 is said to be comprised of 15to 20 percent perfluoroalklyl acrylic copolymer, 1 to 2 percentalkoxylated carboxylic acid, and 3 to 5 percent ethylene glycol.Exemplary characteristics of the composition include a boiling point of100 C at 760 mm Hg and a specific gravity of 1.08. The volatiles areapproximately 80 percent by weight. The pH is 2 to 5. The odor is mild;the concentrate form is that of a semi-opaque liquid; and theconcentrate color is straw white. The composition and characteristics ofZEPEL® 7040 repellent chemical are believed to be substantiallyidentical to those of ZEPEL® 6700 except that the former compositionadditionally contains 7 to 8 percent acetone.

Another major group of water repellent fluorochemicals comprises theScotchgard® water repellent chemicals of 3M Co., St. Paul, Minn. TheScotchgard® fluorochemicals are believed to be aqueously dispersedfluorochemicals in polymeric form. The compositions of two suitableScotchgard® water repellent fluorochemicals are believed to be disclosedin U.S. Pat. Nos. 3,393,186 and 3,356,628, which patents areincorporated herein by reference. Thus, the Scotchgard® fluorochemicalof U.S. Pat. No. 3,356,628 consists of copolymers of perfluoroacrylatesand hydroxyalkyl acrylates. These copolymers are suitable for use as anoil and water repellent coating on a fibrous or porous surface. Theyhave a carbon to carbon main chain and contain recurring monovalentperfluorocarbon groups having from 4 to 18 carbon atoms each and alsohaving recurring hydroxyl radicals. From 20 to 70 percent of the weightof such copolymer is contributed by fluorine atoms in theperfluorocarbon groups and from 0.05 to 2 percent of the weight of thecopolymer is contributed by the hydroxyl radicals. Such copolymer issaid to have improved surface adherability properties as compared to thehomopolymer of a corresponding fluorocarbon monomer.

The Scotchgard® fluorochemical of U.S. Pat. No. 3,393,186 consists ofperfluoroalkenylacrylates and polymers thereof. An exemplary fluorinatedmonomer has the formula: ##STR1##

Wherein R_(f) is a fluorocarbon group having from 3 to 18 carbon atoms,R is hydrogen or methyl, and n is 0-16. Such a water repellentfluorochemical composition is supplied and saturated into the substrateweb as a readily pourable aqueous dispersion.

U.S. Pat. No. 4,426,476 discloses a fluorochemical textile treatingcomposition containing a water-insoluble fluoroaliphatic radical, analiphatic chlorine-containing ester and a water insoluble,fluoroaliphatic radical containing polymer.

U.S. Pat. No. 3,896,251 discloses a fluorochemical textile treatingcomposition containing a fluoroaliphatic radical containing linear vinylpolymer having 10 to 60 weight percent fluorine and a solvent solublecarbodiimide preferably comprising fluoroaliphatic groups. A table inthis patent lists a plurality of prior art fluoroaliphatic radicalcontaining polymers useful for the treatment of fabrics and the priorart patents where such polymers are taught.

U.S. Pat. No. 3,328,661 discloses textile treating solutions of acopolymer of an ethylenically unsaturated fluorocarbon monomer and aethylenically unsaturated epoxy group containing monomer.

U.S. Pat. No. 3,398,182 discloses fluorocarbon compounds useful forfabric treatment that contain a highly fluorinated oleophobic andhydrophobic terminal portion and a different nonfluorinated oleophilicportion linked together by a urethane radical.

Water repellent fluorochemical compositions are preferably utilized tosaturate a starting untreated porous web substrate so that suchcomposition and its constituents wet substantially completely andsubstantially uniformly all portions of the web. Such a saturation canbe accomplished by various well known techniques, such as dipping theweb into a bath of the composition, or padding the composition onto andinto the web, or the like. Padding is the presently preferred method offluorochemical application.

After application of the fluorochemical composition to the web, thewater (or liquid warier) and other volatile components of thecomposition are removed by conventional techniques to provide a treatedweb that contains the impregnated fluorochemical throughout the websubstrate.

In a preferred procedure of fluorochemical controlled placement, a webis substantially completely saturated with an aqueous dispersion of afluorochemical. Thereafter, the resulting impregnated web is compressedto remove excess portions of said dispersion. Finally, the web is heatedto evaporate the carrier liquid. If the fluorochemical is curable, thenthe heating also accomplishes curing. After the fluorochemicaltreatment, the fluorochemical is found only on or in the web structuralelements or fibers and is substantially completely absent from the webinterstices.

The fluorochemical concentration in the treating composition is such asto permit a treated fluorochemical containing web, after volatiles ofthe treating composition are removed, to exhibit a contact angle withwater applied to an outer web surface which is greater than about 90.More preferably, the contact angle provided is greater than about 130.

The web weight add-on provided by the fluorochemical after removal ofvolatiles is usually relatively minor. However, the weight add on canvary with such factors as the nature of web treated, the type of polymercomposition utilized in the next step of the process, the temperature atwhich the composition is applied, the ultimate use contemplated for aweb, and the like.

Typical weight add-ons of fluorochemical are in the range of about 1 toabout 10 percent of the original weight of the web. More preferably,such weight add-ons are about 2 to about 4 weight percent of the weightof the starting fabric.

Durability of a web that has been treated with a fluorochemical anddurability of a web that is subsequently treated with a polymer cansometimes be improved by the conventional process of "sintering". Theexact physical and chemical processes that occur during sintering areunknown. The so-called sintering temperature utilized is a function ofthe fluorochemical composition utilized and such temperature isfrequently recommended by fluorochemical manufacturers. Typically,sintering is carried out at a temperature of about 130° C. to about 160°C. for a period of time of about 2 to about 5 minutes. Acid catalystscan be added to give improved durability to laundering and dry cleaningsolvents.

The fluorochemical is believed to provide more than water or otherrepellent properties to the resulting treated web, particularly sincethe curable polymer is often itself a water repellent. Rather, andwithout wishing to be bound by theory, it is believed that thefluorochemical in a treated web provides relative lubricity for thetreated fibers during the pressure application of the curable polymer.The polymer is applied under pressures which can be relatively high, andthe polymer is itself relatively viscous, as is discussed herein. Inorder for the curable polymer to coat and envelopweb fibers, but notfill web interstitial voids, the fibers of the web may move over andagainst each other to a limited extent, thereby to permit entry of thepolymer into and around the fibers. It is thought that thefluorochemical deposits may facilitate such fiber motion and facilitateenvelopment during the pressure application and subsequent shearingprocessing.

Alternatively, the fluorochemical may inhibit deposition of the polymerat the positions of the fluorochemical deposits which somehow ultimatelytends to cause thin enveloping layers of polymer to form on fibers.

The precise physics and chemistry of the interaction between thefluorochemical and the polymer is not understood. A simple experimentdemonstrates movement of the liquid polymer as influenced by thepresence of the fluorochemical:

A piece of fabric, for example the Red Kap Milliken poplin polyestercotton blend fabric, is cut into swatches. One swatch is treated with anadjuvant, for example a three percent solution of the durablewater-repellent chemical Milease® F-31X. The treated swatch and anuntreated swatch are each positioned at a 45 angle to plumb. A measuredamount, for example one-half ounce, of a viscous polymer composition,for example the Mobay® 2530A/B silicon composition, is dropped onto theinclined surface of each swatch. The distance in centimeters that thecomposition flows downwards upon the surface of the swatch is measuredover time, typically for 30 minutes.

A graphical plot of the flow of the silicone composition respectivelyupon the untreated and treated swatches over time can be prepared, suchas shown in FIG. 1. At the expiration of 30 minutes the viscouscomposition has typically traveled a distance of about 8.8 centimetersupon the treated swatch, or a rate of about 0.29 centimeters per minute.At the expiration of the same 30 minutes, the viscous composition hastypically traveled a lesser distance of about 7.1 centimeters upon theuntreated swatch, or a rate of about 0.24 centimeters per minute.Qualitatively commensurate results are obtainable with other DWRfluorochemical adjuvants that facilitate the viscous flow of polymercompositions in accordance with the invention. Indeed, if desired, thesimple flow rate test can be used to qualify an adjuvant compound forits employment within the method of the invention. The fluorochemicalpretreated web generally increases the surface contact angle of thepolymer while reducing the amount of saturation of the polymer into thefibers themselves.

The fluorochemical treated web is thereafter treated under pressure witha predetermined amount of a curable polymer composition to form a webwhose fibers are preferably substantially completely enveloped with suchcurable polymer and whose outer surfaces and interstices are preferablysubstantially completely free of the curable polymer. The polymer isthereafter cured by heat, radiation, or the like. Even room temperaturecuring can be used. A polymer impregnated, fluorochemical pretreated webcan be interveningly stored before being subjected to curing conditionsdepending upon the storage or shelf life of the treating siliconepolymer composition.

A curable polymer composition utilized in the practice of this inventionpreferably has a viscosity that is sufficient to achieve an internalcoating of the web. Generally, the starting viscosity is greater thanabout 1000 centipoise and less than about 2,000,000 centipoise at ashear rate of 10 reciprocal seconds. It is presently most preferred thatsuch composition have a viscosity in the range of about 5,000 to about1,000,000 centipoise at 25° C. Such a composition is believed to containless than about 1% by weight of volatile material.

The polymer is believed to be typically polymeric and to be commonly amixture of co-curable polymers, oligomers, and/or monomers. A catalystis usually also present, and, for the presently preferred siliconepolymer compositions discussed hereinafter, is platinum or a platinumcompound, such as a platinum salt.

A preferred class of liquid curable silicone polymer compositionscomprises a curable mixture of the following components:

(A) at least one organo-hydrosilane polymer (including copolymers);

(B) at least one vinyl substituted polysiloxane (including copolymers);

(C) a platinum or platinum containing catalyst; and

(D) (optionally) fillers and additives.

Typical silicone hydrides (component A) are polymethylhydrosiloxaneswhich are dimethyl siloxane copolymers. Typical vinyl terminatedsiloxanes are vinyldimethyl terminated or vinyl substitutedpolydimethylsiloxanes. Typical catalyst systems include solutions orcomplexes of chloroplatinic acid in alcohols, ethers, divinylsiloxanes,and cyclic vinyl siloxanes.

The polymethylhydrosiloxanes (component A) are used in the form of theirdimethyl copolymers because their reactivity is more controllable thanthat of the homopolymers and because they result in tougher polymerswith a lower cross-link density. Although the reaction with vinylfunctional silicones (component B) does reportedly take place in 1:1stoichiometry, the minimum ratio of hydride (component A) to vinyl(component B) in commercial products is reportedly about 2:1 and may beas high as 6:1. While the hydrosilation reaction ofpolymethylhydrosilane is used in both so called RTV (room temperaturevulcanizable) and LTV (low temperature vulcanizable) systems, and whileboth such systems are believed to be useful in the practice of thepresent invention, systems which undergo curing at elevated temperatureare presently preferred.

Elastomers produced from such a curing reaction are known to demonstratetoughness, tensile strength, and dimensional stability.

Particulate fillers are known to be useful additives for incorporationinto liquid silicone polymer compositions. Such fillers apparently notonly can extend and reinforce the cured compositions produced therefrom,but also can favorably influence thixotropic behavior in suchcompositions. Thixotropic behavior is presently preferred incompositions used in the practice of this invention. A terminal silanol(Si--OH) group makes such silanol siloxanes susceptible to reaction incuring, as is believed desirable.

It is believed that all or a part of component B can be replaced with aso called silanol vinyl terminated polysiloxane while using an organotincompound as a suitable curing catalyst as is disclosed in U.S. Pat. No.4,162,356. However, it is presently preferred to use vinyl substitutedpolysiloxanes in component B.

A polymer composition useful in this invention can contain curablesilicone resin, curable polyurethane, curable fluorosilicone, curablemodified polyurethane silicones, curable modified siliconepolyurethanes, curable acrylics, polytetrafluoroethylene, and the like,either alone or in combination with one or more compositions.

One particular type of silicone composition which is believed to be wellsuited for use in the controlled placement step of the method of theinvention is taught in U.S. Pat. Nos. 4,472,470 and 4,500,584 and inU.S. Pat. No. 4,666,765. The contents of these patents are incorporatedherein by reference. Such a composition comprises in combination:

(i) a liquid vinyl chain-terminated polysiloxane having the formula:##STR2## wherein R and R1 are monovalent hydrocarbon radicals free ofaliphatic unsaturation with at least 50 mole percent of the R1 groupsbeing methyl, and where n has a value sufficient to provide a viscosityof about 500 centipoise to about 2,000,000 centipoise at 25 C;

(ii) a resinous organopolysiloxane copolymer comprising:

(a) (R²)₃ SiO₀.5 units and SiO₂ units, or

(b) (R³)₂ SiO₀.5 units, (R³)₂ SiO units and SiO₂ units, or

(c) mixtures thereof, where R² and R³ are selected from the groupconsisting of vinyl radicals and monovalent hydrocarbon radicals free ofaliphatic unsaturation, where from about 1.5 to about 10 mole percent ofthe silicon atoms contain silicon-bonded vinyl groups, where the ratioof monofunctional units to tetrafunctional units is from about 0.5:1 toabout 1:1, and the ratios of difunctional units to tetrafunctional unitsranges up to about 0.1:1;]

(iii) a platinum or platinum containing catalyst; and

(iv) a liquid organohydrogenpolysiloxane having the formula: ##EQU1## inan amount sufficient to provide from about 0.5 to about 1.0silicon-bonded hydrogen atoms per silicon-bonded vinyl group of abovecomponent (i) or above subcomponent (iii) of, R_(a) is a monovalenthydrocarbon radical free of aliphatic unsaturation, and has a value offrom about 1.0 to about 2.1, b has a value of from about 0.1 to about1.0, and the sum of a and b is from about 2.0 to about 2.7, there beingat least two silicon-bonded hydrogen atoms per molecule.

Optionally, such a composition can contain a finely divided inorganicfiller (identified herein for convenience as component (v)).

For example, such a composition can comprise on a parts by weight basis:

(a) 100 parts of above component (i);

(b) 100-200 parts of above component (ii);

(c) a catalytically effective amount of above component (iii), which,for present illustration purposes, can range from about 0.01 to about 3parts of component (iii), although larger and smaller amounts can beemployed without departing from operability (composition curability) asthose skilled in the art will appreciate;

(d) 50-100 parts of above component (iv), although larger and smalleramounts can be employed without departing from operability (curability)as those skilled in the art will appreciate; and

(e) 0-50 parts of above component (v).

Embodiments of such starting composition are believed to be availablecommercially from various manufacturers under various trademarks andtrade names.

As commercially available, such a composition is commonly in thetwo-package form (which are combined before use). Typically, thecomponent (iv) above is maintained apart from the components (i) and(ii) to prevent possible gelation in storage before use, as thoseskilled in the art appreciate. For example, one package can comprisecomponents (i) and (ii) which can be formulated together with at leastsome of component (ii) being dissolved in the component (i), along withcomponent (iii) and some or all of component (v) (if employed), whilethe second package can comprise component (iv) and optionally a portionof component (v) (if employed). By adjusting the amount of component (i)and filler component (v) (if used) in the second package, the quantityof catalyst component (iii) required to produce a desired curablecomposition is achieved. Preferably, component (iii) and the component(iv) are not included together in the same package. As is taught, forexample, in U.S. Pat. No. 3,436,366 (which is incorporated herein byreference), the distribution of the components between the two packagesis preferably such that from about 0.1 to 1 part by weight of the secondpackage is employed per part of the first package. For use, the twopackages are merely mixed together in suitable fashion at the point ofuse. Component (vi) is optionally mixed into the polymer compositionjust prior to applying to a porous web. Other suitable silicone polymercompositions, without additives, are disclosed in the following U.S.patents:

U.S. Pat. No. 4,032,502 provide compositions containing a linearpolydiorganosiloxane having two siloxane bonded vinyl groups permolecule, organosiloxane that is soluble in such linearpolydiorganosiloxane and comprised of a mixture of a polyorganosiloxaneand a polydiorganosiloxane, platinum-containing catalyst, a platinumcatalyst inhibitor, and a reinforcing silica filler whose surface hasbeen treated with an organosilicone compound.

U.S. Pat. No. 4,108,825 discloses a composition comprising atriorganosiloxy end-blocked polydiorganosiloxane, anorganohydrogensiloxane having an average of at least 2.1 silicon-bondedhydrogen atoms per molecule, a reinforcing silica filler having asurface treated with an organosilicone compound, a platinum catalyst,and ceric hydrate. Such silicone polymer composition is desirable when aweb is being prepared which has flame retardant properties.

U.S. Pat. No. 4,162,243 discloses a silicone composition of 100 parts byweight triorganosiloxy end-blocked polydimethylsiloxane, reinforcingamorphous silica that is surface treated with organosiloxane groups,organchydrogensiloxane, and platinum catalyst.

U.S. Pat. No. 4,250,075 discloses a liquid silicone polymer compositionthat comprises vinyldiorganosiloxy end-blocked polydiorganosiloxane,polyorganohydrogensiloxane, platinum catalyst, platinum catalystinhibitor, and carbonaceous particles. Such a silicone polymercomposition is useful when a web of this invention is being preparedthat has electrically conductive properties.

U.S. Pat. No. 4,427,801 discloses a curable organopolysiloxane of liquidtriorganosiloxy end-blocked polydiorganosiloxane wherein thetriorganosiloxy groups are vinyl dimethylsiloxy orvinylmethylphenylsiloxy, finely divided amorphous silica particlestreated with mixed trimethylsiloxy groups and vinyl-containing siloxygroups, organopolysiloxane resin containing vinyl groups,organohydrogensiloxane, and a platinum containing catalyst.

U.S. Pat. No. 4,500,659 discloses a silicone composition of liquidtriorganosiloxy end-blocked polydimethylsiloxane wherein thetriorganosiloxy units are dimethylvinylsiloxy ormethylphenylvinylsiloxy, a reinforcing filler whose surface has beentreated with a liquid hydroxyl end-blocked polyorganosiloxane which isfluorine-substituted, a liquid methylhydrogensiloxane, and aplatinum-containing catalyst.

U.S. Pat. No. 4,585,830 discloses an organosiloxane composition of atriorganosiloxy end-blocked polydiorganosiloxane containing at least twovinyl radicals per molecule, an organohydrogensiloxane containing atleast two silicone-bonded hydrogen atoms per molecule, aplatinum-containing hydrosilation catalyst, optionally a catalystinhibitor, a finely divided silica filler, and a silica treating agentwhich is at least partially immiscible with said polydiorganosiloxane.

U.S. Pat. No. 4,753,978 discloses an organosiloxane composition of afirst diorganovinylsiloxy terminated polydiorganosiloxane exhibiting aspecified viscosity and having no ethylenically unsaturated hydrocarbonradicals bonded to non-terminal silicon atoms, a seconddiorganovinylsiloxy terminated polydiorganosiloxane that is misciblewith the first polydiorganosiloxane and contains a vinyl radical, anorganohydrogensiloxane, a platinum hydrosilation catalyst, and a treatedreinforcing silica filler.

U.S. Pat. No. 4,785,047 discloses silicone elastomers having a mixtureof a liquid polydiorganosiloxane containing at least two vinyl or otherethylenically unsaturated radicals per molecule and a finely dividedsilica filler treated with a hexaorganodisilazane which mixture is thencompounded with additional hexaorganodisiloxane.

U.S. Pat. No. 4,329,274 discloses viscous liquid silicone polymercompositions that are believed to be suitable and which are comprised ofvinyl containing diorganopolysiloxane (corresponding to component B),silicon hydride siloxane (corresponding to component A) and an effectiveamount of a catalyst which is a halogenated tetrameric platinum complex.

U.S. Pat. No. 4,442,060 discloses a mixture of 100 parts by weight of aviscous diorganopolysiloxane oil, 10 to 75 parts by weight of finelydivided reinforcing silica, 1 to 20 parts by weight of a structuringinhibitor, and 0.1 to 4 parts by weight of 2,4-dichlorobenzoyl peroxidecontrolled cross-linking agent.

Silicone resin compositions shown in Table I below have all been used inthe practice of this invention. Such compositions of Table I arebelieved to involve formulations that are of the type hereinabovecharacterized.

                  TABLE I                                                         ______________________________________                                        Illustrative Starting Silicone Polymer Compositions                           Manufacturer                                                                            Trade Designation                                                                            Components.sup.(1)                                   ______________________________________                                        Mobay     Silopren ® LSR 2530                                                                      Vinyl-terminated                                                              polydimethyl/siloxane with                                                    fumed silica, methyl                                                          hydrogen                                             Mobay     Silopren ®                                                                LSR 2540/01                                                         Dow Corning                                                                             Silactic ® polysiloxane                                                   595 LSR                                                             General Electric                                                                        SLE 5100       polysiloxane                                         General Electric                                                                        6108                                                                General Electric                                                                        5110                                                                Dow Corning                                                                             2103                                                                General Electric                                                                        SLE 5106       siloxane resin solution                              General Electric                                                                        SLE 5300       polysiloxane                                         General Electric                                                                        SLE 5500       polysiloxane                                         Shin-Etsu KE1917                                                              Shin-Etsu DI 1940-30                                                          SWS Silicones                                                                           Liquid Rubber BC-10                                                                          silicone fluid with silicone                         Corporation              dioxide filler and curing                                                     agents.                                              ______________________________________                                         .sup.(1) Identified components do not represent complete composition of       the individual products shown.                                           

When a polymer composition of a silicone polymer and a benzophenone ispressured into a porous web as taught herein, protection of an organicweb against ultraviolet radiation is improved, and the degradationeffects associated with ultraviolet light exposure are inhibited, as maybe expected from prior art teachings concerning the behavior ofbenzophenones.

Ultra-violet-absorbing agents contemplated for use in the practice ofthe present invention include uvA absorbers such asbenzophenone-8-methyl anthranilate; benzophenone-4; benzophenone-3; 2,4-dihydroxy-benzophenone; uvB absorbers such as p-aminobenzoic acid(PABA); pentyl dimethyl PABA; cinoxate; DEA p-methoxycinnamate;digalloyl trioleate; ethyl dihydroxypropyl PABA; octocrylene, octylmethoxycinnamate, otcyl salicylate, glyceryl PABA; homosalate; lawsoneplus dihydroxyacetone; octyl dimethyl PABA;2-phenylbenzimidazole-5-sulfonic acid; TEA salicylate; sulfomethylbenzylidene bornanone; urocanic acid and its esters, and physicalbarriers such as red petrolatum and titanium dioxide.

To prepare a silicone polymer composition which incorporates abenzophenone, one preferably admixes the benzophenone with the siliconepolymer composition at the time of use. The benzophenone component canbe regarded as, or identified herein for convenience as the modifiercomponent (vi). On the same parts by weight basis above used, acomposition of this invention contains from about 0.1 to about 15 partsof component (vi), although the preferred amount is from about 0.3 toabout 10 parts of component (vi) and smaller amounts can be used, ifdesired, without departing from the spirit and scope of the invention.

One class of derivitized benzophenones useful in the practice of thisinvention is characterized by the generic formula:

(2) ##STR3##

where R¹ and R² are each selected from the group consisting of hydroxyl,lower alkoxy, and hydrogen, and n and m are each an integer of 1 or 2.Examples of substituted benzophenones of the above formula include thesubstances shown below.

                  TABLE II                                                        ______________________________________                                        Substituted Benzophenones                                                                               Commercially available                              ID.                       specified under                                     No.  Name                 trademark from BASF                                 ______________________________________                                        1    2,4,dihydroxybenzophenone                                                                          "Uvinul" 400.sup.1                                  2    2-hydroxy-4-methoxy-benzophenone                                                                   "Uvinul" M-40                                       3    2,2',4,4'-tetrahydroxybenzophenone                                                                 "Uvinul" D-50                                       4    2,2'-dihydroxy 4,4'-dimethoxy                                                                       "Uvinul" D-49                                           benzophenone                                                             5    mixed tetra-substituted benzophenones                                                              "Uvinul" 49D                                        ______________________________________                                         .sup.1 Presently most desired substituted benzophenone                   

Another class of derivitized benzophenones useful in the practice ofthis invention is characterized by the generic formula:

(3) ##STR4##

where:

R³ is a lower alkyl radical.

An example of a substituted benzophenone of formula (3) is:2-ethylhexyl-2-cyano3,3-diphenylacrylate (available from BASF under thetrademark "Uvinul N-539").

In the preceding formulas (3) and (4), the term "lower" has reference toa radical containing less than about 8 carbon atoms. The contact angleexhibited by a silicone composition used in this invention varies withthe particular web which is to be saturated therewith. However, thecontact angle of water is generally lower for the non-treated side thanthe treated side. A combination of the processed web, the siliconepolymer and the fluorochemical generally produces higher water contactangles than webs treated only with fluorochemicals. The performance of apolymer composition may be determined by the nature of a previouslyapplied saturant such as a fluorochemical. Suitable startingcompositions include 100% liquid curable silicone rubber compositions,such as SLE5600 A/B from General Electric, Mobay LSR 2580A/B, DowCorning Silastic® 595 LSR and Silastic® 590 which when formulated withsubstituted benzophenone as taught herein will form a contact angle ofmuch greater than 70 degrees, and typically of 90+ degrees, with typicalporous webs (such as fabrics) that have a residue of fluorochemical upon(and within) the web from a prior saturation.

The polymer composition used in the practice of this invention can alsocarry additives into the three-dimensional structure of the web duringthe pressured application. Further, it is preferable, that any additivesand/or modifiers be bound into the cured composition permanently aslocated in the three-dimensional structure of the web. Particularly inthe case of fabrics, this desirably positions the additives and/ormodifiers mainly on surface portions of the encapsulated yarns andfibers in positions where they typically are beneficially located andmaintained, or on the surfaces of the internal layer, or on the surfacesof the web, or some combination thereof. When necessary, the polymercomposition, the web or fabric used, and the particular additive and/ormodifier compounds can be altered to create specific functionalproperties such as adhesiveness, antimicrobial activity, bloodrepellency, conductivity, fire resistance, flexibility, good hand, stainresistance, ultraviolet absorption capabilities, and other functionsdescribed by this invention.

Silicone polymers, when compounded with additives and/or modifiers,produce desirable properties. For example, a fine particle silica isadded to silicone polymer as a filler or reinforcing agent to increasethe hardness and reduce the stickiness. Carbon black is added whenelectrical conductivity is required. Red iron oxide improves heatresistance. Zinc oxide is used for heat conductivity. Aluminum hydrateis added for extra electrical track resistance. Various pigments areused for coloring. Such solid additives and/or modifiers can be added bymixing with silicone polymer at a certain ratio. Mixing of the siliconepolymer is usually performed by a mixer, or the like. Care should betaken to add the additive (and/or modifier) powders slowly enough toprevent balls of high additive and low silicone content from forming andfloating on top of the silicone polymer which leads to poor dispersion.Poor dispersion will result in an uneven distribution of the additiveand/or modifier on and within the web. If much additive and/or modifieris being added, several separate additions and cross blending betweenthem will assure good dispersion. The sequence of addition is alsoimportant. For instance, when extending fillers are added, they shouldbe added after the reinforcing fillers. Color, when used, may be addedat this stage. The catalyst is added at the final stage or is part ofthe co-blended polymer composition. Care should be taken to be sure thecompound temperature is cool enough to prevent unexpected curing of thesilicone polymer.

Liquid additives and/or modifiers can be added by directly mixing withsilicone polymer or finely dispersing in the silicone polymer. Additivesand/or modifiers can also be added in a homogeneous form such asdissolving in suitable organic solvents or water, or in a heterogeneousform such as latex. For example, hydrophobic polyurethanes orfluorocarbon polymers can be dispersed in water by addition ofemulsifiers or surfactants in a emulsion form or latex.

A wide variety of additives, agents, or modifiers, herein usedinterchangeably, can be used in accordance with the practice of thisinvention to produce porous webs that retain the functional propertiesof the agents incorporated within the web. It is impossible to list incertainty all of the agents and modifiers that can be used in accordancewith the practice of the present invention. Many of the additives usedin the plastics industry are described in handbooks and can be used inaccordance with the practice of this invention. Two such handbooks arePlastics Additives: An Industrial Guide, by Ernest W. Flick (NoyesPublications 1986), and Chemical Additives For The Plastics Industry:Properties, Applications, Toxicologies, by the Radian Corporation (NoyesData Corp. 1987), herein incorporated by reference. The charts belowlist (1) additives known to work in accordance with the practice of thisinvention, (2) additives that are substantially similar in physicaland/or chemical properties to the additives that are known to work inaccordance with the practice of this invention, and (3) additives thatwere unknown in the art as of the printing of the above referencedhandbooks. Some of these agents are discussed in greater detail insubsequent sections.

    ______________________________________                                        Adhesive Agents                                                               Epoxy-resin                                                                   Co-oligomer                                                                   Phenolic resins                                                               Polyurea resins                                                               Polyolefins                                                                   Polyamides                                                                    Polysiloxanes                                                                 Polysulfides                                                                  Polyvinyl esters                                                              Neoprene                                                                      Polyurethanes                                                                 Polyacetal resin, with one or more members selected from the group            consisting of isocyanate and isothiocyanate compounds.                        Anti-Static Agents                                                            Fatty acid esters and their derivatives                                       Long-chain amines                                                             Amides                                                                        Quaternary ammonium salts                                                     Polyoxyehtylene derivatives                                                   Polyhydric alcohols and their derivatives                                     1,2-epoxides such as 1,2-epoxyhexane, 1,2-epoxyoctane, 1,2-                   epoxynoname, 1,2-epoxydecane, 1,2-epoxydodecane, 7,8-                         epoxyoctadecane, 9,10-epoxyoctadecane, 5,6-epoxydodecane, 7,8-                epoxyoctadecane, 2,3-epoxydodecane, 5,6-epoxydodecane, 7,8-                   epoxyoctadecane, 9,10-epoxyoctadecane, 10,11-epoxyeicosane.                   Epoxides reacted under acid or alkaline catalyst conditions with              ethylene glycols or 1,2-propylene glycols. Example catalysts are BF           etherate, sulfuric acid, sodium methylate, and lithium methylate.             Preferable ethylene or propylene glycols are mono-, di, tri and tetra.        Biocidal Agents                                                               Halogens and halogen based compounds such as iodine, chloroazodin,            chlorinated cyanuric acid derivatives, and chloramine derivatives.            Antibiotics                                                                   Anti-virals such as zidovudine                                                Nonoxynol-9                                                                   Phenols and phenolic compounds such as o-phenylphenol, o-benzyl-p-            chlorophenol, p-tert-amylphenol, bisphenols such as hexachlorophene,          dichlorophene, methylene-bis(4-chlorophenol), fentichlor, and                 trichlosan.                                                                   Quarternary ammonium salts such as cetrimide, benzalkonium                    chloride, cetylpridinium chloride, laurolinium acetate, dequalinium           chloride, hedaquinium chloride, polyquaternium 1.                             Zinc oxide, Z-N-octyl-4-isothiazole-3-one                                     Phenyl mercuric acetate                                                       Skin disinfectants such as alcohols, mercurials, silver compounds,            neomycin                                                                      Water disinfectants such as chlorine and sodium hypochlorite                  Air disinfectants such as propylene glycol, lactic acid, glycolic acid,       and levulinic acid                                                            Gaseous disinfectants such as ethylene oxide, β-propiolactone, and       formaldehyde                                                                  Clothing disinfectants such as neomycin                                       Methyl dimethyl propoxylene ammonium chloride                                 Polyiodide material like Pentaiodid                                           Acid salts derived from hydrochloric, methane sulfonic,                       ethanesulfonic, isoethionic, lactic, and citric acids.                        Trichlorocarbon                                                               Blood Repellents                                                              Antimicrobial or biocidal agents                                              Monoaldehyde                                                                  Iodophors such as povidone-iodine, polyvinyl pyrrolidone (PVP) or             povidone USP, butyl cellosolve albumin-povidone-iodine complex                Polyethylene glycol mono (nonylphenyl) ether                                  Diethyl ether                                                                 Phenol resin                                                                  Urea resin                                                                    Urethane modified epoxy resin                                                 Organosilicon quaternary ammonium salts                                       Dyes and Pigments                                                             Azoic dyes                                                                    Cationic Dyes                                                                 Sulfur dyes                                                                   Nigrosine                                                                     Carbon black                                                                  Electrical Conductive Agents                                                  Metal particles or fillers                                                    Zinc oxide                                                                    Stannic oxide                                                                 Indium oxide                                                                  Tungsten and tungsten carbide                                                 Carbon black                                                                  Graphite and metal coated graphite                                            Conductive polymers                                                           Silver, nickel, copper, aluminium, gold                                       Rhodium                                                                       Ruthenium                                                                     Molybdenum                                                                    Iridium                                                                       Platinum                                                                      Palladium                                                                     Electromagnetic Shielding Agents                                              Hypophosphorous                                                               Carbon-phenol resin compound                                                  Fillers                                                                       Carbon                                                                        Molecular sieves                                                              Fumed silica                                                                  Colloidal silica                                                              Flame Retardant Agents                                                        Aluminium hydroxide                                                           Borax                                                                         Tetrakis (hydroxymethyl)                                                      Phosphonium chloride                                                          Potassium hexafluoro zirconate                                                Potassium hexafluoro titanate                                                 Polyamide                                                                     Polyimide                                                                     Poly-parabanic acid                                                           Polyether sulfone, polyether ether keton, polyetherimide                      Fluoroplastic resin films                                                     Plyphenylene sulfide                                                          Magnesium hydroxide                                                           Silicone trated magnesium oxide                                               Polybenzimidazole                                                             Non-flame durable fibers with flame durable fibers of metal such as           stainless steel, copper, nickel                                               Carbon or carboniziable compositions                                          Kevlar ™                                                                   Nomex ™                                                                    Retardant powder fillers such as alumina trihydrate                           Kaolin, gypsum and hydrated clay incorporated with                            polydimethylsiloxanes                                                         Polypropylene, polybutylene                                                   Metal carboxylic acid salts containing at least 6 carbon atoms.               Calcium, barium and strontium compounds                                       Carboxylic acid salts: calcium stearate, barium stearate and strontium        stearate, stearates, isostearates, oleates, palmitates, myristates,           laurates,                                                                     undecylenates, 2-ethylhexanoates, hexanoates                                  Salts of the following acids may be suitable: sulfinic, sulfonic,             aromatic sulfenic, sulfamic, phosphinic and phosphoric acids                  Polyolefins such as low density polyethylene and high density                 polyethylene                                                                  Polypropylene, polybutylene                                                   Copolymers such as polystyrene, polycarbonates                                Polyesters, polyamides, polycaprolactams                                      Ionomers, polyurethanes, co- & ter-polymers                                   Acrylonitrile, butadiene, styrene, acrylic polymers, acetal resins,           ethylene-vinyl acetate                                                        Polymethylpentene                                                             Polyphenylene oxide, polyphenylene oxide-polystyrene blends or                copolymers with optional arganic halides such as decabromodiphenyl            oxide, dechlorane plus a chlorinated alicyclic hydrocarbon, and               aluminum trihydrate                                                           Flexibility Inducing Agents                                                   Diglycidyl ether of linoleic acid dimer                                       Diglycidyl ether of polyethylene glycol                                       Diglycidyl ether of polypropylene glycol                                      Diglycidyl ether of alkylene oxide adduct of bisphenol A                      Urethane prepolymer                                                           Urethane modified epoxy resin                                                 Polycarboxyl compounds                                                        Polycaprolactone                                                              Phenoxy resin                                                                 Flattening Agents                                                             Amorphous Silica 1-2% by total resin weight, such as OK 412,                  produced by DeGussa, Inc. (Frankfurt, Germany), available through             its pigment division in Teterboro, NJ.                                        Silica                                                                        Micronized polyethylene                                                       Grease Resistant Agents                                                       Carboxymethylcellulose, methylcellulose, methylethylcellulose,                hydroxypropylmethylcellulose, hydroxypropylcellulose                          Hand Altering Agents                                                          Protein structures made to imitate some borrowed property on or near          the surface of the polymers.                                                  Natural and synthetic beta-pleated sheet proteins                             Hydrolized silk such as "Crosilk,"]a commercially hydrolized silk             protein (Croda, Inc. New York, NY). Crosilk is a 10,000 molecular             weight protein made by hydrolizing silk, and is comprised of 17               different amino acid segments, ranging in percent by weight of 0.1%           to 20.3%.                                                                     Polyolefin fiber or fabric                                                    Humidity Controlling Agents                                                   Solid copper salts, preferably organic copper salts such as copper            formate, copper acetate, copper oxalate and others.                           Ion-Exchange Agents                                                           Duolite C255H ™ by Diamond Shamrock                                        Ammonium salts                                                                Chloride                                                                      Compounds and materials exhibiting acidic or basic functionality              Nitrate                                                                       Zeolite beta, zeolite chabazite (low calcium)                                 Light Fastness-Inducing Agents                                                Ink dyes                                                                      Cationic dyes                                                                 Acid dyes                                                                     Monosulfonic acid, disulfonic acid, sulfonic acid-carboxylic acid             Light-Reflective Agents                                                       Titanium oxide                                                                Zinc oxide                                                                    Mildew Resistant Agents                                                       Thiazolylbenzimidazole                                                        Zinc phosphite                                                                Derivatives of phenol                                                         Derivatives of benzothiazole                                                  Organosilicon quaternary ammonium salt                                        Processing Agents                                                             Crosslinking inhibitors                                                       Rheological agents                                                            Hydrophilic polymers                                                          Polyvinyl alcohol                                                             Proteins                                                                      Silk protein                                                                  Fibroin                                                                       Collagen                                                                      Radio Frequency Shielding Agents                                              Photoresistive films made of polyamide or SOG (Spin On Glass)                 Magnetic films                                                                Piezoelectric                                                                 Photoresistive films as a switchable EMI barrier                              Rot Resistant Agents                                                          Zinc chloride, chromated zinc chloride                                        Stain Resistant Agents                                                        A mixture of phenyl vinyl ether/maleic diacid copolymer and Z-(4-             hydroxy-methyl-phenoxy)-ethyl vinyl ether/maleic diacid copolymer             and a copolymer obtained by the reaction of phenyl vinyl ether 2-(4-          hydroxy-phenoxy)-ethyl vinyl ether and maleic anhydride                       Erional ™ NBS, Intratex N ™                                             Mesitol, FX-369, CB-130, Nylofixan P                                          Therapeutic Agents                                                            Antibiotics                                                                   Chemotherapeutic compounds                                                    Hormones                                                                      Analgesics such as aspirin                                                    Vitamins                                                                      Spermacides such as ricinleic acid, p-diisobutylphenoxypolyethoxyethanol,     boric acid, and nonoxynol-9.                                                  Drugs                                                                         Growth Factors                                                                Molecular sieves or other enclosed forms containing all of the above.         Thermal Conductive Agents                                                     Aluminium particles such as aluminum nitride and alumina                      Fillers such as silver                                                        Graphite                                                                      Silicon carbide                                                               Boron nitride                                                                 Diamond dust                                                                  Synthetic resin                                                               Ultraviolet-Absorbing Agents                                                  Benzophenone and its derivatives                                              Aryl group-substituted benzotriazole compound                                 Cinnamic acid esters                                                          Benzoxazale                                                                   4-thiazolidone compounds                                                      Titanium dioxide                                                              Zinc oxide                                                                    Water Repellent Agents                                                        Fluoroalkylsilane                                                             Alkylsilane                                                                   Dimethylpolysiloxane                                                          Fluorine-type water repellent agent (Asahi Guard AG710)                       Silazene compound e.g., (CH.sub.3).sub.3 SiNH--Si(CH.sub.3).sub.3 (6)         Stearic acid salts                                                            Zirconium compounds                                                           Fluorosilicon type KP-801                                                     Epoxy group-containing organosiloxanes                                        Polysiloxanes containing fluorine atoms                                       Perfluoroakyl-silicone-KP801                                                  Dimethylamino-silicone                                                        Wax                                                                           ______________________________________                                    

Some additives and/or modifiers may or may not be combined with thethixotropic material prior to application to the porous substrate. Thesematerials are applied to the surface of the porous substrate bydepositing or metering, or by other like means.

Other additives and/or modifiers suitable for use in the practice of thepresent invention include compounds that contain reactive sites,compounds that facilitate the controlled release of agents into thesurrounding environment, catalysts, compounds that promote adhesionbetween the treating materials and the substrate, and compounds thatalter the surface chemistry of articles produced from the treatedsubstrates.

Reactive sites contemplated in the practice of the present inventioninclude such functional groups as hydroxyl, carboxyl, carboxylic acid,amine groups, and the like, that promote physical and/or chemicalinteraction with other materials and compounds. For example, themodifier may be an enzyme or metal that catalyzes a specific reaction.Alternatively, the modifier may bind an agent. The phrase "capacity tobind," as used herein, refers to binding by both covalent andnon-covalent means. Polyurethane is an example of a modifier withreactive sites that specifically bind iodine, the agent. A protein is anexample of a modifier with reactive sites that specifically bind anantibody, the agent. The resulting articles are useful, for example,where iodine release is desirable (e.g., as a disinfectant), due to thetendency of iodine to sublime under ambient conditions.

The modifier or agent may also be a biologically active or "bioactivemolecule" such as an enzyme, antibody, antigen, or other binding proteinsuch as biotin or avidin. For example, the modifier may be an antibodyand the agent, a target protein, and the like. Or, the modifier may be aprotein, and the agent, a target antibody. Such embodiments areparticularly useful to the field of medical diagnostics.

Alternatively, the modifier may be capable of binding any proteinaceousmaterial regardless of its bioactivity, such as polypeptides, enzymes ortheir active sites, as well as antibodies or antibody fragments. Theseembodiments, as contemplated in the practice of the present invention,are applicable to both research- and industrial-scale purificationmethods.

Depending on the end use of the treated material, a variety of modifierscontaining reactive sites can be used. For example, modifiers can beemployed that bind agents that are airborne organic contaminants. Theparticular compound employed as the modifier will depend on the chemicalfunctionality of the target agent and could readily be deduced by one ofskill in the art.

Also contemplated by the present invention is the use of modifiers thatare capable of promoting the release of an agent from the treated web.For example, where the agent is being released from a thixotropicmaterial that is hydrolytic, the modifier may be a hygroscopic compoundsuch as a salt that promotes the uptake of water. As water is drawn intothe material, the thixotropic material degrades by hydrolysis, thusreleasing the agent. Alternatively, the modifier may promote the releaseof an agent from the treated web by creating pores once the resultingarticle is placed in a particular environment. For example, awater-soluble hygroscopic salt can be used to induce pore formation inthixotropic materials when placed in a humid or aqueous environment.Thus, dissolution of the salt promotes the release of the agent from thetreated substrate. Other such modifiers that promote the release of anagent from materials are known to those of skill in the art. Agentssuitable for use in these embodiments include therapeutic agents,biologically active agents, pesticides, biocides, iodine, and the like.

Also contemplated for use in the practice of the present invention asthe modifier component are hydrogels. Hydrogels are polymeric materialsthat are capable of absorbing relatively large quantities of water.Examples of hydrogel forming compounds include polyacrylic acids, sodiumcarboxymethylcellulose, polyvinyl alcohol, polyvinyl pyrrolidine,gelatin, carrageenan and other polysaccharides,hydroxyethylenemethacrylic acid (HEMA), as well as derivatives thereof,and the like.

Control of the pressurized application step can be provided at a numberof areas since the shear process is sensitive to the viscosity of thepolymer composition both at atmospheric pressure and at superatmosphericpressure. The ambient temperature affecting the polymer as it isapplied, and the pressure-induced temperature changes occurring duringcontrolled placement of the polymer also play roles in viscosity andtherefore the shear process. Of course, the chemical make-up of thepolymer composition also plays a role in the shear process and assistsin the formation of an internal layer and/or internal encapsulation ofthe fibers or structural elements of the web.

The amount of polymer utilized and the weight add-on thereof are againvariable and dependent upon several things such as the treated web, thedesired end use of the web, cost and the like. Web weight add-ons can beas little as about 1 to 5 weight percent up to about 200 weight percentof the untreated web. For producing breathable, water-repellent fabricwebs of this invention, weight add-ons are preferably in the range ofabout 10 to about 100 weight percent of the weight of the untreated web.

The fluorochemical saturant composition may also contain a bondingagent. The bonding agent can facilitate the bonding of the waterrepellent chemical and/or the impregnate to the three-dimensionalstructure of the web within which it is saturated. Mobay Silopren™bonding agent type LSR Z 3042 and Norsil 815 primer are representativecompositions that can be used to facilitate bonding of the waterrepellent chemicals and/or impregnant to and within the web. Use of thebonding agents is not essential to the practice of this invention, butmay improve bonding of the fluorochemical and/or the polymer compositionto fibers.

The fluorochemical particularly, and also the bonding agents when used,are preferably affixed to the three-dimensional structure of the webprior to the controlled placement of polymer within the web. Completeaffixing is not necessary for the fluorochemical. The fluorochemicalwill apparently facilitate the pressured application of a polymercomposition even if the fluorochemical is not preliminarily fixed withinor located within the web being treated. However, fixing, especially bysintering, appears to cause the water repellent chemicals to flow and tobecome better attached to the three-dimensional structure of the web. Inthis regard, a lesser amount of fluorochemical will remain in placebetter, and will better facilitate the subsequent pressured applicationof the polymer, if the sintering or insolubilizing step is performedprior to such a pressured application.

After fluorochemical saturation followed by controlled polymer placementand curing, a web may have a surface contact angle with the polymer ofgreater than about 70 degrees, and more typically greater than about 90degrees. Web pressures can involve transverse force or pressure in therange of tens to thousands of pounds per square inch of web surface.

Similar to the functional qualifications achieved by the use of afluorochemical in the preferred saturating pretreatment step, thepolymer introduced by the pressured application step can be defined byits functional qualifications. For example, the silicone polymerproduces a contact angle with a fluorochemical treated web of greaterthan about 70 degrees. The contact angle of a web with a fluorochemicalwill be within a range of about 90 degrees to about 180 degrees whilethe contact angle of a fluorochemically treated web with the siliconepolymer will be within a range of about 70 degrees to about 180 degrees.

The contact angle exhibited by the silicone polymer can be, if desired,qualified against the particular web saturated with the particularfluorochemical saturant. The selection of a suitable silicone polymercomposition may be determined by the nature of the previously appliedfluorochemical saturant. The fluorochemical saturant and siliconepolymer compositions are, however, not critical to the practice of thisinvention since wide respective compositional ranges may be involved. Inparticular, a substantially undiluted liquid silicon rubber which isavailable from suppliers, such as GE, Dow Corning, and Mobay-Bayer, willcharacteristically form a contact angle of much greater than about 70degrees, and typically greater than about 90 degrees, with typicalporous webs (such as fabrics) that have a residue of fluorochemical upon(and within) the web resulting from a prior saturation.

The polymer composition can carry additives into the three-dimensionalstructure of the web in the pressured application steps of the method ofthe invention. Further, the polymer composition, when cured, is capableof adhering to structural elements, fibers, yarns, and the like, and anyadditives dispersed therein. Thus, additives are positioned adjacent toor on surfaces of structural elements, yarns, fibers and the like, in aposition where they can be beneficial.

The energy can also be used to drive additives and/or modifiers tovarious selected positions within the porous web. During this stage, theviscosity of the thixotropic material becomes low enough and theapplication thickness thin enough such that additives and/or modifiersare able to move with either the sufficient mechanical energy or waveinduced energy. Depending on the affinity of the additive and/ormodifier for the thixotropic impregnant material as compared to thesubstrate/impregnant and impregnant/air interfaces, the additive and/ormodifier will migrate to a particular region within the web. Thismigration is referred to herein as "surface blooming." The extent andrate of migration can be controlled by controlling the viscosity andthickness of the impregnant and the mobility of the particular additiveand/or modifier. Both characteristics depend on the amount of energyprovided to the system. Due to the nature of the thixotropic material,the additives and/or modifiers can be fixed at any location along theirmigratory path. For example, the amount of energy directed at theimpregnant and web is decreased as the additives and/or modifiersmigrate into the target positions. As the viscosity of the thixotropicimpregnant rises, the additives and/or modifiers become essentiallylocked in place. This cycling of energy may be repeated in this stage,as well as in Stages 4 and 5, discussed below, until the additivesand/or modifiers are finally moved and fixed into the preselectedposition.

Surface blooming is a term describing both the migration and exactorientation of the additive and/or modifier on or near the surface ofthe polymer. There seems to be either such a thin layer of the polymer(mono layer) or an actual breaking of the surface structure of thepolymer so as to allow the exposure of the additive and/or modifier. Itcan also be applied to a time dependent effect whereby over time andexposure to movement and ambient conditions, the additive and/ormodifier becomes exposed, as with time released agents.

The phenomenon referred to as "surface blooming" is believed to be theresult of several factors working in conjunction, some of which aredescribed above. The alternating silicon and oxygen (siloxane) bondscreate a flexible backbone, and rotation is fairly free about the Si--Oaxis, especially with small substituents, e.g., methyl, on the siliconatoms. Rotation is also free about the Si--C axis in methylsiliconcompounds. As a result of the freedom of motion, the intermoleculardistances between methylsiloxane chains are greater than betweenhydrocarbons. and intermolecular forces are smaller.Polydimethylsiloxane (PDMS) contains a very surface active group, --CH₃,whose activity is presented to best effect by the unique flexibility ofthe backbone. A more complete description of the surface characteristicsof polydimethylsiloxanes is available in The Surface Activity ofSilicones: A Short Review, Michael J. Owen, Ind. Eng. Chem. Prod. Res.Dev., v. 19, p97 (1980); and the Encyclopedia of Polymer Science andEngineering 2d Ed., Wiley, New York, v. 15, Silicones (1985-90); allherein incorporated by reference.

Additional control over the positioning of additives and/or modifiersmay be exerted during the curing process in Stage 8, discussed below.This control relates to another mechanism of additive and/or modifiermovement during treatment as described in the discussion of Stage 8below.

Energy sources contemplated for use in the practice of the presentinvention include subjecting the curable, thixotropic material and oneor more modifiers to shearing conditions ("treating materials"). Forexample, the shearing conditions may be provided by passing the treatingmaterial and web in contact with one or more blades at a fixedorientation with respect to the blades. The blades may be either rigidor flexible to accommodate a greater variety of web materials. Forexample, a more rigid blade may be used if the web is soft and flexible.Similarly, a flexible blade may be used if the web is hard and rigid.

Alternatively, the energy may be provided by passing the treatingmaterials and web through rollers at a controllable pressure. Othersources of energy contemplated for use in the practice of the presentinvention include thermal energy, ultrasonic energy, electron beam,microwave, and electromagnetic radiation.

Examples of additives that are dispersible in effective amounts in aviscous polymer composition typically at a concentration of about 0.1 to20 weight percent (based on total composition weight) includeultraviolet absorbers, flame retardants, aluminum hydroxide, fillingagents, blood repellents, flattening agents, optical reflective agents,hand altering agents, biocompatible proteins, hydrolyzed silk, and thelike. Hydrolyzed silk is a texturing agent that imparts a substantiallysilky feel to a fabric treated in accordance with the method of theinvention regardless of whether or not such treated web or fabric isitself silk.

Examples of other polymer dispersible agents include those affectingthermal conductivity, radiation reflectivity, electrical conductivity,and other properties. For example, if a metallic sheen and/or thermal orelectrical conductivity or infrared background blending is desired,powdered metals may be dispersed therein.

The pressured application of the polymer is sensitive to the viscosityof the polymer composition. Temperature affects the polymer compositionby reducing or altering its viscosity. Shear-induced temperature changesoccurring during application or during subsequent shear processing ofthe polymer can affect viscosity. The chemical composition of thepolymer also plays a role in the treating process and effects in thetreatment of web structural elements (including fibers) and theregulation of the filling of interstices and open cell voids.

Various machines and procedures can be used for performing the processof the invention. Illustrative machines and processes of use which aresuitable for use in the practice of this invention, are described inU.S. application Ser. No. 08/407,191, filed Mar. 17, 1995 and herebyincorporated by reference. A preferred apparatus for carrying out thepresent invention is described below.

The apparatus employed in the present invention functions first to applyand preferably concurrently to shear thin and place a polymercomposition, with one or more additives and/or modifiers optionallymixed in the composition, into a web under pressure. Such polymercomposition is then reintroduced, distributed, and metered in acontrolled manner in the web with the aid of transversely appliedshearing force and compressive force such that the polymer compositionbecomes distributed in the web so that additives and/or modifiers areoriented on and within the (a) thin film encapsulation of the individualfibers and filaments, (b) the controlled placement of the internalcoating, and (c) some combination of (a) and (b). During treatment, theweb is longitudinally tensioned and the pressurized application and thesubsequent shearing and compressive actions are successivelyaccomplished in localized zones preferably extending generally laterallyacross the web (that is, generally perpendicularly to the direction ofsuch longitudinal web tensioning) using transversely applied forceexerted locally against surface portions of the web during eachcontrolled placement and shearing operation. The web is conveniently andpreferably, but not necessarily, moved longitudinally relative to suchlaterally extending web processing zones. In treating short lengths of afabric, the blades may be moved relative to a stationary length offabric. The pressurized application, shearing and compressing steps arepreferably carried out successively or sequentially. Such zones arethemselves preferably at stationary locations while the web is moved,but if desired, the web can be stationary while the zones are moved, orboth. The result is that the polymer composition flows into the web andis distributed internally generally uniformly to a predeterminable andcontrollable extent.

Some additives and/or modifiers, due to their physical and chemicalproperties, cannot be incorporated on and/or within a web bypre-treating the web or by mixing the additives and/or modifiers intothe polymer composition. Such additives and/or modifiers can betopically applied to the web after the pressured, shear thinning stagedescribed above, but before curing. Once topically applied, theadditives and/or modifiers are forced into the web by passing throughthe exit nip rolls. The additives and/or modifiers will adhere to thepolymer composition that forms encapsulated fibers, an internal layer,or some combination of the above.

FIG. 5 depicts a schematic, side elevational view of a preferredapparatus for practicing the methods of the present invention. In thisembodiment a continuous web 302 is moved under tension along a webpathway from a supply roll 301 to a take-up roll 327.

The primary tension is a result of the differential rate between thedriven entrance pull stand designated as 306 and the driven exit pullstand designated as 322, whereby the exit pull stand 322 is driven at arate faster than the entrance pull stand 306. Other controllable factorswhich effect tension are the diameters of blade rolls 309, 314, 316,318; the vertical depth of blades 311, 315, 317; the durometer of theentrance pull stand rolls 304, 305 and rubber roll 321 of the exit pullstand, and the friction as the web passes under the blades. Blade roll316 can optionally be a nip roll, as shown with the top roll 329. Thisallows for the creation of multiple tension zones to help shear thin thepolymer composition and place one or more additives and/or modifiers onor within the web.

Web 302 passes between the nip of the two rolls 304 and 305 of the entrypull stand 306. The entry nip is adjustable to produce a force of fromabout 100 lbs. to about 5 tons on the web, passing between the tworolls. The weight of top roll 305 provides an even distribution of forcethroughout the web width. Web 302 is flattened at this point and theinterstitial spaces are reduced laterally and longitudinally. Bottomroll 304 has micro-positioning capability to provide for gap adjustmentand alignment. The top roll 305 composition is chosen based on thedurometer of a urethane or rubber roll.

Web 302 continues to move along past idler roll 308 and blade roll 309and forms an entry angle α and an exit angle β with blade 311. Blade 311is illustratively shown in FIG. 4. In FIG. 4, dimensions A, B, C, D, andE are typically and exemplarily illustrated as, respectively, about 31/2inches, about 11/2 inches, about 2 inches, about 1/2 inch, and about5/16 inch. The narrow edge is preferably milled to a tolerance of about1/10,000 inch continuously along the edge surface of each blade which istypically and illustratively about 38 inches long. Each of the cornersof the narrow edge is preferably and illustratively a hard (not beveledor ground) angular edge. Preferably, the combination of the leading edgecondition and the two surfaces (the front and the bottom) that meet atthe leading edge are RMS 8 or better in grind and/or polish. Forpurposes of the apparatus of FIG. 5, the blade in FIG. 4 has a leadingedge 250 and a trailing edge 260. Entry angle α can be varied byadjusting: (a) the height and diameter of blade rolls 309 and 314, (b)the horizontal position of blade rolls 309 and 314, (c) the angle ofblade 311, and (d) the height of blade 311. Similarly, the entry andexit angles of blades 315 and 317, can be varied by adjusting the samedevices surrounding each blade.

For illustrative purposes, increasing the height and diameter of bladeroll 309 decreases entry angle α. Rotating blade 311 clockwise, with web302 running left to right, increases entry angle α. Likewise, rotatingblade 311 counter-clockwise, with web 302 running left to right,decreases entry angle α. Decreasing the distance between blade roll 309and blade 311 decreases entry angle α. Increasing the downward depth ofblade 311 into web 302 decreases entry angle α.

The angle of blades 311, 315, and 317 are completely changeable andfully rotational to 360°. The fully rotational axis provides anopportunity for more than one blade per rotational axis. Therefore, asecond blade having a different thickness, bevel, shape, resonance,texture, or material can be mounted. Ideally the apparatus contains twoor three blades per blade mount. The blade mounts are not shown.

The force or pressure of blade 311 applied against web 302 is determinedby the vertical positioning of blade 311 in the blade mount. The greaterthe downward depth of blade 311, the greater the force or pressure.Blade pressure against the web is also accomplished through the tensionof the web as described above.

The same line components that affect entry angle α, also affect exitangle β. Any changes in the height, diameter, or horizontal positioningof blade rolls 309 and 314, affects exit angle β. If the angle of blade311 is rotated clockwise as described above, entry angle α increases,thus decreasing exit angle β.

As web 302 moves from left to right in FIG. 5, polymer, optionally mixedwith one or more additives and/or modifiers, is deposited on web 302with polymer applicator or dispersion means 310. Polymer applicator 310can be a pump, a hose, or any available application device for applyingpolymer onto the surface of the web. Polymer applicator 310 is locateddirectly in front of blade 311. The polymer is immediately shearthinned, placed into, and extracted from web 302 by the leading edge ofblade 311, thus controlling the amount of polymer remaining in web 302.The bevel of blade 311 can effect entry angle α and the sharpness of theleading edge of blade 311. A sharper leading edge has a greater abilityto push the weave or structural elements of web 302 longitudinally andtraversely, increasing the size of the interstitial spaces. As the webpasses the leading edge of blade 311, the interstitial spaces snap backor contract to their original size.

As web 302 moves from left to right in FIG. 5, the process of shearthinning and placing polymer into and extracting it out of web 302 isrepeated at subsequent blades 315 and 317, thus controllably placing thepolymer throughout web 302. Web 302 then passes over idler roll 319 andadditives and/or modifiers are topically applied to web 302 by additiveapplicator or dispersion means 328. Additive applicator 328 can be apump, or hose, or any application device for applying additives onto thesurface of the web. Additive applicator 328 is located directly in frontof the exit pull stand 322.

Web 302 then passes between driven exit pull stand 322 which consists ofrolls 320 and 321. Pull roll 320 is a driven roll proportionally drivenat a predetermined rate slower than entry roll 304. Pull roll 321 doesnot apply pressure so much as it achieves a high degree of surface areain which web 302 must come into contact with. The larger the surfacearea, the higher the degree of contact friction. Pull roll 321 can beadjusted to have sufficient downward force to eliminate any slippagebetween web 302 and pull roll 320.

After web 302 passes from exit stand 322, it then moves into an oven 323for curing. Rolls 324, 325, and 326 provide a tension regulating meansand also serve to provide a cooling pathway for web 302 as it emergesfrom oven 323 before passing onto take-up roll 327.

The cure temperature of oven 323 is thermostatically controlled to apredetermined temperature for web 302 and the polymers used. Machineruns of new webs are first tested with hand pulls to determine adhesion,cure temperature, potentials of performance values, drapability,aesthetics, etc. The effect on web 302 depends on the temperature ofoven 323, dwell time and curing rate of the polymer. Web 302 may expandslightly from the heat.

Oven 323 functions to cure the polymer composition that is controllablyplaced into web 302. Oven 323 can be operated with gas or other energysources. Furthermore, oven 323 could utilize radiant heat, inductionheat, convection, microwave energy or other suitable means for effectinga cure. Oven 323 can extend from about 12 to 20 yards, with 15 yardslong being convenient.

Curing temperatures from about 320° F. to about 500° F., applied fortimes of from about two minutes to about thirty seconds (depending onthe temperature and the polymer composition) are desirable. If a curingaccelerator is present in the polymer, curing temperatures can bedropped down to temperatures of about 265° F. or even lower (with timesremaining in the range indicated).

The cure temperature of oven 323 and the source and type of cure energy,are controlled for a number of reasons. The cure temperature of oven 323is controlled to achieve the desired crosslinked state; either partialor full. The source and type of energy can also affect the placement ofthe polymer and additives. In place of an oven, or in combination withan oven, a source of radiation can be employed (electron beams,ultraviolet light, or the like) to accomplish curing, if desired. Forexample, by using a high degree of specific infrared and some convectionheat energy for cure, some additives can be staged to migrate and/orbloom to the polymer surfaces.

Oven cure dwell time is the duration of time the web is in oven 323.Oven cure dwell time is determined by the speed of the oven's conveyorand physical length of the oven. If the dwell time and temperature for aparticular web is at maximum, then the oven conveyor speed would dictatethe speed of the entire process line or the length of the oven wouldhave to be extended in order to increase the dwell time to assure properfinal curing of the web.

Take-up roll 327 is operated at approximately the same speed as supplyroll 301. When the rotational speeds of take-up roll 327 are notsynchronized with rotational speeds of supply roll 301, the tension rollcombination of rolls 324, 325, and 326 can be used to reduce web slack.

Web speed is proportional to the variable speed of the motor whichdrives entrance pull stand 306 and exit pull stand 322. Web speed caneffect the physics of the polymers as web 302 passes under blades 311,315, and 317. Web transport speeds can vary widely; for example, fromabout two yards per minute to about ninety yards per minute.

FIG. 1 illustrates the phenomenon referred to herein as "thixotropiclooping." This figure represents the viscosity changes of a polymercomposition applied to a web by the apparatus shown in FIG. 5. For thepurposes of demonstrating the general phenomenon, each blade is the samesize and shape and each blade is positioned the same so that the shearrate at each blade is identical.

As the polymer composition comes in contact with the first blade, theshear stress reduces the viscosity of the polymer composition.Immediately after the first blade, the polymer begins to increase inviscosity, but never returns to its initial viscosity. As it comes incontact with the second blade, again the viscosity drops, but not assevere as with the first blade. Immediately after the second blade, theviscosity increases, but not to its initial viscosity. This phenomenonoccurs again at the next blade and would continue at subsequent bladesuntil the polymer reached its minimum viscosity.

A general process for making a porous web of this invention comprisesthe steps of: optionally pre-treating a flexible, porous web with amodifier by saturation methods known in the art; tensioning a flexible,porous web as above characterized; optionally mixing one or moreadditives and/or modifiers with a curable shear thinnable polymercomposition; applying the mixed curable shear thinnable polymercomposition, described above, to at least one web surface; and thenmoving over and against one surface of the tensioned web a uniformlyapplied localized shear force to: shear thin the optionally mixedpolymer composition, uniformly place the composition within the web, atleast partially individually encapsulate or envelop surface portions ofat least some of said fibers through the web matrix or position saidcomposition in a desired web internal region or some combination ofboth. Some additives and/or modifiers can then optionally be topicallyapplied and pressed onto and into the web by the exit pull stand.Thereafter, the web is subjected to conditions sufficient to cure thecomposition in said web. Curing is accomplished by heat, by radiation,or both.

A presently preferred process for making a fluorochemical and siliconeresin treated web having breathability, water resistance, rewashability,and one or more additives and/or modifiers, which is adapted forcontinuous operation comprises the successive steps of: impregnating theweb with a fluorochemical, longitudinally tensioning the fluorochemicalimpregnated web while sequentially first applying to one surface thereofa curable silicone polymer composition with one or more additives and/ormodifiers therein and concurrently applying a transversely exertedlocalized compressive force against said surface, and moving over saidsurface of the web substantially rigid shearing means which exertstransversely an applied, localized shear force against said surface toshear thin the polymer and wipe away exposed portions of siliconepolymer composition on said surface, thereby forming an internal layerof silicone polymer and/or enveloping at least some of the fibers orpassageways through the matrix, or both; optionally topically applyingone or more additives and/or modifiers; and curing the silicone polymercomposition in the web.

The additives and/or modifiers may also be selectively positioned duringthe final stage of the treatment process. When a diluent is incorporatedinto the polymer composition, the additives and/or modifiers may bemoved by controlling the volatization of the diluent. As the diluent isdriven to the air/polymer surface by heat, it carries the additivesand/or modifiers with it to the surface. As the polymer compositioncures, its viscosity increases thus fixing the additives and/ormodifiers in position. Appropriate diluents include water and lowmolecular weight silicones and solvents such as aromatic solvents (e.g.,toluene), low molecular weight ketones (e.g., acetone, methyl ethylketone, and the like. Positioning of the additive and/or modifier inthis manner can be controlled by controlling among other variables, theamount of energy directed at the treating materials and substrate andthe amount and type of diluent in the polymer composition. Positioningof additives and/or modifiers can also occur by the pressuredapplication of additives and/or modifiers onto and into the web. Justprior to passing the treated web through the exit nip rolls, one or moreadditives and/or modifiers can be topically applied to the web, therebyforcing the additive(s) and/or modifier(s) onto and into one or moresurfaces of the web. The additive and/or modifier can adhere to the weband/or the polymer composition in the web. Preferably the additive(s)and/or modifier(s) adheres to the polymer composition that encapsulatesthe individual fibers or filaments, that forms an internal layer, thatfills some of the interstitial spaces of the web, or that produces somecombination of the foregoing.

The following text concerns the theory of the invention as it is nowunderstood; however, there is no intent herein to be bound by suchtheory.

The presently preferred polymer composition used in the treatment ofwebs by this invention is a non-Newtonian liquid exhibiting thixotropic,pseudoplastic behavior. Such a liquid is temporarily lowered inviscosity by high pressure shear forces.

One aspect of the invention is a recognition that when high forces orsufficient energy are applied to curable polymer compositions, theviscosities of these materials can be greatly reduced. When theviscosity is repeatedly reduced, the result is one of thixotropicallylooping or massaging the viscosity rheology crosslink opportunities andoverall orientation of one or more additives and/or modifiers on and/orwithin the (a) thin film encapsulation of the individual fibers andfilaments, (b) the controlled placement of the internal coating, and (c)some combination of (a) and (b). Thixotropic looping is illustrativelyand qualitatively shown in FIG. 1, for an apparatus containing threeblades. Conversely, when subjected to curing, the same liquidcomposition sets to a solid form which can have a consistency comparableto that of a hard elastomeric rubber. The internal and externalrheological control of polymer materials achieved by the presentinvention is believed to be of an extreme level, even for thixotropies.When subjected to shear force, the polymer composition is shear thinnedand can flow more readily, perhaps comparably, for illustrativepurposes, to water.

The invention preferably employs a combination of: (i) mechanicalpressure to shear thin and place a polymer composition into a porousweb; (ii) an optional porous web pretreatment with a water repellentchemical, such as a fluorochemical, which is theorized to reduce thesurface tension characteristics of the web and create a favorablesurface contact angle between the polymer composition and the treatedweb which subsequently allows, under pressure and shear force exertedupon an applied polymer composition, the production and creation of aninternal coating or layer which envelopes fibers or lines cell walls ina localized region within the web as a result of polymer flow in the webor which encapsulates the fibers within the web; and (iii) a polymercomposition impregnant preferably having favorable rheological andviscosity properties which responds to such working pressures andforces, and is controllably placed into, and distributed in a web. Thiscombination produces a web having the capability for a high degree ofperformance. This product is achieved through pressure controlledplacement and applied shear forces brought to bear upon a web so as tocause controlled movement and flow of a polymer composition and one ormore additives and/or modifiers into and through a web. Preferably,repeated compressive applications of pressure or successive applicationsof localized shear forces upon the polymer in the web are employed.

By the preferred use of such combination, a relationship is establishedbetween the respective surface tensions of the polymer and the web,creating a specific contact angle. The polymer responds to a waterrepellent fluorochemical pretreatment of the substrate so as to permitenhanced flow characteristics of the polymer into the web. However, theboundary or edge of the polymer is moved, preferably repeatedly, inresponse to applied suitable forces into the interior region of a porousweb so as to cause thin films of the polymer to develop on the fibersurfaces and to be placed where desired in the web.

Thixotropic behavior is preferably built into a polymer used in theinvention by either polymer selection or design or additive/fillerdesign. For example, it now appears that thixotropic behavior can beaccentuated by introducing into a polymer composition certain additivesthat are believed to impart enhanced thixotropy to the resultingcomposition. A lower viscosity at high shear rates (during applicationto a web) is believed to facilitate polymer flow and application to aweb, whereas a polymer with high viscosity, or applied at a low shearrate (before and/or after application) actually may retard or preventstructural element (including fiber) envelopment or encapsulation.

Illustratively, the practice of this invention can be considered tooccur in stages:

In stage 1, a silicone polymer composition impregnant is prepared. Itcan be purchased commercially and comes in typically two partsdesignated as A and B. For example, in a silicone polymer composition,as taught in U.S. Pat. No. 4,472,470, a base vinyl terminatedpolysiloxane is the A part, while a liquid organohydrogensiloxanecontrolled crosslinking agent is the B part. Certain remainingcomponents, such as a resinous organopolysiloxane copolymer and aplatinum catalyst may (or can) apparently initially be in either part Aor part B.

Stage 2 can be considered to involve the mixing of such a product'sparts with or without additives. Changes in viscosity can be obtainedand measured based on applied shear rates and shear stresses. Suchchanges can be experienced by a polymer with or without additives. Up toa 99% reduction in viscosity of a liquid silicone polymer composition isbelieved to be obtainable by the shear forces involved in the shearthinning and forcing of a silicone polymer composition impregnant into aweb and almost simultaneously extracting the correct amounts out.Thereafter, a very substantial increase in polymer viscosity is believedto be obtainable taking into account these same factors. Normally, themost significant factor is now believed to be the shear gradient thattypically reduces the viscosity of the polymer below the starting orrest viscosity.

Stage 3 can be considered to be the pressure introduction stage. Up to a99% reduction of the polymer viscosity is believed to be obtainable dueto the applied shear forces, elapsed time, temperature, radiation and/orchemical changes. Thereafter, a signficant increase or even more in theresulting polymer viscosity is believed to be obtainable. In this stage,partial curing of the polymer may take place. Most commonly, polymerviscosity is substantially decreased during the pressure controlledplacement Stage 3 by the application of shear forces.

Stage 4 can be considered to be the first stage internal matrixdispersing and reintroduction with metering, and also recovery andrecycle of excess polymer. Typically, within this Stage 4, the shearforces cause a substantial but temporary lowering of polymer viscosity,causing it to flow upon and into the three-dimensional structure of theweb. The initial viscoelastic character of the polymer is typicallytheorized to be recovered almost immediately after shear forces areremoved.

Stage 5 can be considered to be a second stage internal matrixdispersing and reintroduction with metering and also recovery andrecycling of excess polymer. The variations in the viscosity of thepolymer are equivalent to Stage 4. The viscosity of the polymer is againlowered causing it to flow within the web. Because of the application ofrepeated shear force induced reductions in viscosity, the thixotropicbehavior of a polymer may not undergo complete recovery, following eachapplication of shear force and the viscosity of the polymer may notrevert to its original placement values. The polymer composition isbelieved to have the capacity to form enveloping internal coating in apredetermined region wherein the interstices or open cells aresubstantially completely filled within the three-dimensional matrixconstituting a web during the time intervals that the is caused to flowunder pressure in and about matrix components. In between these times,the polymer may recover substantially all of its initial high viscosity,although perhaps slightly less so with each repeated application ofshearing pressure or force.

Stage 6 can be considered the optional application of additives and/ormodifiers. Some additives and/or modifiers, due to their physical andchemical properties, cannot be incorporated on and within a web bypre-treating the web or by mixing the additives and/or modifiers intothe polymer composition. Such additives and/or modifiers can betopically applied to the web after the pressured, shear thinning stagedescribed above, but before curing. Once topically applied, theadditives and/or modifiers are forced into the web by passing throughthe exit nip rolls. The additives and/or modifier can adhere to thepolymer composition or to the individual fibers of the web. Preferably,the additives and/or modifiers will adhere to the polymer compositionthat fills the warp filled interstitial spaces, forms encapsulatedfibers, an internal layer, or some combination of the above.

Stage 7 can be considered to be occurring just as curing is begun, andjust as heat or other radiation is introduced.

Stage 8 can be considered to be occurring with regard to the exertion ofcontrol of curing. Typically, at least a partial curing (includingcontrolled cross-linking and/or polymerizing) is obtained by relativelylow temperatures applied for relatively short times. For example, whenlight cotton, nylon, or similar fabrics are being treated, temperaturesunder about 350°, applied for under about 10 seconds, result in partialcuring.

In one embodiment of the present invention, the curable, thixotropicmaterial plus additives and/or modifiers form a porous film having anaverage pore size in the range of 0 to 10 microns (although not zeromicrons). Porous films are produced by the addition of pore-formingagents to the thixotropic material. Examples of pore-forming agentsinclude low molecular weight polymers and oligomers that can besubsequently washed from the treated substrate using appropriatesolvents and co-solvents that are known by those skilled in the art.

In preferred embodiments of the present invention, sufficient energy isused to selectively position the additives and/or modifiers at specificlocations within the porous web. As employed herein, the phrase"selectively positioned" refers to the localization of additive and/ormodifier materials at desired regions within the porous web. "Selectivepositioning" is achieved by controlling a phenomenon unique to thinfilms known as "migratory surface bloom." Migratory surface bloom refersto the ability of an additive and/or modifier to migrate to the surfaceand assume its multi-dimensional conformation.

The phenomena referred to as "surface blooming" is believed to be theresult of several factors working in conjunction, such as the size andshape of the additive(s) and/or modifier(s), the thickness of the thinfilm, and the characteristics of polydimethylsiloxanes. The alternatingsilicon and oxygen (siloxane) bonds create a flexible backbone, androtation is fairly free about the Si--O axis, especially with smallsubstituents, e.g., methyl, on the silicon atoms. Rotation is also freeabout the Si--C axis in methylsilicon compounds. As a result of thefreedom of motion, the intermolecular distances between methylsiloxanechains are greater than between hydrocarbons. and intermolecular forcesare smaller. Polydimethylsiloxane (PDMS) contains a very surface activegroup, --CH₃, whose activity is presented to best effect by the uniqueflexibility of the backbone. A more complete description of the surfacecharacteristics of polydimethylsiloxanes is available in The SurfaceActivity of Silicones: A Short Review, Michael J. Owen, Ind. Eng. Chem.Prod. Res. Dev., v. 19, p97 (1980); and the Encyclopedia of PolymerScience and Engineering, v. 15, Silicones, (Wiley 1987); allincorporated herein by reference. In the present invention, the extentof surface bloom is controlled by controlling the amount of energydirected at the treating materials and web.

In one embodiment of the present invention, the additive and/or modifieris selectively positioned substantially on the application surface ofthe porous web. In another embodiment of the present invention, theadditive and/or modifier is selectively positioned substantially on thesurface opposing the application surface of the porous web.Alternatively, where the porous web is derived from discrete elementssuch as fibers that are encapsulated, the additive and/or modifier canbe selectively positioned substantially within the encapsulatedmaterial.

FIG. 2 is a schematic vector diagram illustrating the surface tensionforces acting at the vertex boundary line of a liquid contact angle on aplanar solid surface. It illustrates how surface tension forces might bemeasured between a silicone polymer composition and a fiber of a web (ora fabric) as treated by the invention.

For the purposes of the present invention, the term "surface tension"can be considered to have reference to a single factor consisting ofsuch variables as intermolecular, or secondary, bonding forces, such aspermanent dipole forces, induced forces, dispersion or nonpolar van derWaals forces, and hydrogen bonding forces. The strong primary bondingforces at an interface due to a chemical reaction are theorized to beexcluded from surface tension effects; however, it is noted that even asmall degree of chemical reactivity can have a tremendous influence onwetting effects and behavior affected by surface tension.

The unique feature of poly-dimethylsiloxanes is their high surfaceactivity. Pure poly-dimethylsiloxanes typically exhibit surface tensionvalues of 21 dynes/cm, which is higher than only fluorocarbons. Theprevailing explanation for this phenomenon is the dense packing ofmethyl groups at the surface of the poly-dimethylysiloxanes. The lowsurface tension of poly-dimethylsiloxanes gives them surface-activeproperties both in aqueous and organic solutions. This phenomenon isfurther described in David T. Floyd's article: Organo-Modified SiliconeCopolymers for Cosmetic Use, Cosmetic and Pharmaceutical Applications ofPolymers, p. 49-72, Plenum Press (New York 1991), herein incorporated byreference.

Surface tension is believed to induce wetting effects which caninfluence the behavior of a polymer composition impregnant relative tothe formation of either a fiber enveloped layer therewith in a fibrousporous web, fiber encapsulation or both. For example, adhesion istheorized to be a wetting effect. Spontaneous adhesion always occurs forcontact angles less than about 90°. However, for a combination of arough surface and a contact angle over 90°, adhesion may or may notoccur. In fact, roughness becomes antagonistic to adhesion, and adhesionbecomes less probable as roughness increases.

Also, penetration is theorized to be a wetting effect. Spontaneouspenetration occurs for contact angles less than about 90°, and does notoccur for contact angles over about 90°. The roughness of a solidsurface accentuates either the penetration or the repellency action, buthas no influence on which type of wetting takes place.

In addition, spreading is theorized to be a wetting effect. Retractionoccurs for contact angles over 90° or over planar surfaces for anycontact angle. However, spontaneous spreading for contact angles lessthan 90°, especially for small contact angles, may be induced by surfaceroughness. FIG. 3 is a graph relating the contact angle over a smoothsolid surface as a function of θ and i that apply respectively, toadhesion (I cos θ+1), penetration (i cos θ), and spreading (i cos θ1).

Regions of adhesion versus abhesion, penetration versus repellency, andspreading versus retraction are shown by shaded areas. FIG. 3illustrates what is theorized to be the relationship of a siliconepolymer composition to silicone polymer composition solids in a treatedweb as regards such factors as adhesion, penetration, spreading, andretraction.

For purposes of this invention, the term "wetting" is used to designatesuch processes as adhesion, penetration, spreading, and cohesion. Ifwetting transpires as a spontaneous process, then adhesion andpenetration are assured when the solid surface tension exceeds theliquid surface tension. Surface roughness promotes these spontaneouswetting actions. On the other hand, no such generalizations can be madewhen the solid surface tension is less than the liquid surface tension.

Surface tension is measured by S.T.L. units for liquid and by S.T.S.units for solids; both units are dyns/centimeter. When S.T.S. is lessthan S.T.L., then wetting is less ubiquitous and prediction of wettingbehavior is more difficult. However, by taking advantage of theliquid/solid contact angle that forms when a liquid retracts over asolid, it is possible to calculate with reasonable accuracy the wettingbehavior that can be expected. The reduction in liquid surface area canbe computed in terms of the contact angle that the liquid makes with thesolid surface. Contact angles are always measured in the liquid phaseThere is a point of equilibrium where the surface tension forces becomebalanced.

By measuring the contact angle of a liquid on a solid, the wettingbehavior of the liquid polymer composition can be measured.

The present invention also includes a web comprising a web that has beentreated with a curable thixotropic polymer composition, the web beingadapted to be substantially impermeable to liquids, permeable to gases;and selectively impermeable or permeable to particles. The process ofmaking the web selectively impermeable or permeable to particles ormolecules is disclosed in U.S. Pat. No. 5,912,116, issued on Jun. 15,1999 which is incorporated herein by reference.

Products that can be manufactured from breathable barrier webs accordingto the present invention include, but are not limited to, foul weathergarments, surgical gowns, protective webbing material that can be wornover hospital gowns, patient gowns, surgical scrub suits, sterilizationwrappers (CSR wrap), cover gowns including protective webbing material,isolation gowns, hamper bags, jump suit, surgical masks, work aprons,surgical drapes laboratory coats, wound dressings, absorbent garmentsincluding, but not limited to, diapers, incontinent briefs, trainingpants, head bands, wrist bands, socks, underpants and the like.

Garments that can utilize barrier webs according to the presentinvention are described, for example, in U.S. Pat. No. 4,991,232(hospital gown), U.S. Pat. No. 5,368,584 (disposable diaper and thelike), U.S. Pat. No. 5,304,161 (incontinent pad and diaper), U.S. Pat.No. 5,318,554 (incontinent diaper), U.S. Pat. No. 5,342,335, (disposableabsorbent products) U.S. Pat. No. 5,318,554 (absorbent articles), U.S.Pat. No. 5,304,161 (multilayer absorbent article), U.S. Pat. No.5,290,269 (fabric for hygienic product), U.S. Pat. No. 5,147,345 (highefficiency diaper) U.S. Pat. No. 5,019,062 (bicomponent material fordiapers), U.S. Pat. No. 4,828,556 (breathable barrier for incontinentgarments) U.S. Pat. No. 4,758,239 (breathable barrier) U.S. Pat. No.4,578,072 (leak resistant diaper) U.S. Pat. No. 4,560,380 (disposabletherapy diaper) all of which are incorporated by reference.

A particularly useful incontinent brief is shown in FIG. 7. Thedisposable or non-disposable, breathable incontinence brief 10 consistsof four parts. An outer shell or pant 15, the barrier web made accordingto the present invention is a breathable or non-breathable sheddingshield 20, a disposable or non-disposable absorbent pad 25. The outershell or pant 15 is a barrier web made according to the presentinvention is breathable but void resistant. The incontinence brief hasholes 13 for the legs of the wearer. The shedding shield 20 can beeither breathable or non-breathable but is impermeable to bodily fluidsand provides a dry patch that remains in contact with the skin. Theshedding shield 20 can be fastened on one end 23 or both ends 23 and 24to create either a pocket or a flap. The fastening means can bestitching or velcro. An absorbent pad 25 is enveloped in a foam ornonwoven wrapper which optionally can be treated with an antimicrobialagent such as iodine. (See Example 22) The pad can also optionally betreated with disinfectants and anti odor agents. The disposableabsorbent pad 25 and wrapper are inserted under the shedding shield. 20The shedding shield 20 allows the voided bodily fluids to be absorbeddown, around and under the breathable shield while the shield remainsdry. In this embodiment, the absorbent pad 25 is larger than theshedding shield 20 and overlaps the edges of the shedding shield 20.FIG. 8 is a cross-section view of the incontinence brief along sectionlines 8--8.

In another embodiment shown in FIG. 9, the disposable or non-disposable,breathable brief 50 consists of four parts. an outer shell or pant 55, abreathable or non-breathable shedding shield 60 and a plurality ofdisposable or non-disposable absorbent pads 65. The incontinence briefhas holes 53 for the legs of the patient. In this embodiment, the outershell or pant 55 is a barrier web made according to the presentinvention and is breathable but void resistant. The shedding shield 60is fastened at one end 62 to create either a pocket or a flap andfastened at the opposite end 63 to create a pocket 57. At least one endis fastened by velcro or remains unfastened to allow access to thedisposable absorbent pad or pads 65. The shedding shield can bepermeable or impermeable to bodily fluids. One or more pockets 57 whichcontain the disposable absorbent pad or pads 65 are inserted or formedinto the outer shell. The absorbent pads 65 optionally are enveloped ina foam or nonwoven wrapper which optionally can be treated with anantimicrobial agent such as iodine. (See Example 22) The pad can alsooptionally be treated with disinfectants and anti odor agents. FIG. 10is a cross-section view of the incontinence brief along section lines10--10.

With respect to bandages and surgical gauze, the present invention isparticularly useful in that various wound healing agents can beincorporated into the polymer on the web and thereby aid in the healingof the wound which is physical contact with the bandage or surgicalgauze prepared according to the present invention. These agents include,but are not limited to, various growth factors such basic fibroblastgrowth factor (bFGF), acidic fibroblast growth factor (aFGF), nervegrowth factor (NGF), epidermal growth factor (EGF), insulin-like growthfactors 1 and 2, (IGF-1 and IGF-2), platelet derived growth factor(PDGF), tumor angiogenesis factor (TAF), vascular endothelial growthfactor (VEGF), corticotropin releasing factor (CRF), transforming growthfactors α and β (TGF-α and TGF-β), interleukin-8 (IL-8);granulocyte-macrophage colony stimulating factor (GM-CSF); theinterleukins, and the interferons.

Other agents that can incorporated into the barrier webs of the presentinvention are acid mucopolysaccharides including, but are not limited toheparin, heparan sulfate, heparinoids, dermatan sulfate, pentosanpolysulfate, chondroitin sulfate, hyaluronic acid, cellulose, agarose,chitin, dextran, and carrageenin.

Proteins that are especially useful as wound healing agents include, butare not limited to, collagen, cross-linked collagen, fibronectin,laminin, elastin, and cross-linked elastin and hyaluronic acid orcombinations or fragments thereof.

The fabric is especially suited as a barrier to prevent or control thespread of infectious microorganisms, especially in career apparel forhealth care workers. The webs made according to the present inventionare particularly useful in environments where there is a risk of bloodcontamination. The career apparel from webs made according to thepresent invention can be manufactured so that microbial transmissionthroughout the fabric is inhibited, but air flow is not blocked.

Another advantage of the barrier webs prepared according to the presentinvention is the capability of manufacturing webs that can selectivelyexclude microorganisms based on the size of the microorganisms.Accordingly, for those applications where only large microorganisms area problem, such as certain bacteria, protozoa or fungi, the barrier webcan be manufactured so that these larger microorganisms are excluded.The physical size comparison is shown in the following table:

    ______________________________________                                                          Size or Size Range                                          Organism          (microns)                                                   ______________________________________                                        Effective Porosity of the Web                                                                   0.025 to 100                                                Viruses                                                                       Foot & Mouth      0.008-0.012                                                 Influenza         0.070-0.080                                                 Rabies            0.100-0.150                                                 HBV               0.042-0.047                                                 HCV               0.027-0.030                                                 HIV               0.080-0.110                                                 Ebola             ≈0.970                                              φX174 bacteriaphage                                                                         0.025-0.027                                                 Bacteria                                                                      Escherichia coli  0.50-3.0                                                    Staphylococcus aureus                                                                           0.80-1.0                                                    Spirillum volutons                                                                              13-14                                                       Gas Molecules                                                                 Water vapor       0.0004                                                      ______________________________________                                    

In addition, the webs made according to the present invention can bemanufactured with antimicrobial or disinfecting agents incorporated intothe polymer layer. Among the many chemicals (including nutrients such asO₂ and fatty acids) that are bacteriostatic and even bactericidal atsufficiently high concentrations, the term "disinfectant" is generallyrestricted to those chemicals that are rapidly microbiocidal at lowconcentrations. In contrast to most chemotherapeutic agents, whichinteract with various active metabolic systems, most disinfectants acteither by dissolving lipids from the cell membrane (detergents, lipidsolvents) or by damaging proteins or nucleic acids (denaturants,oxidants, alkylating agents, sulfhydryl reagents).

For example, a fabric can be treated according to the present inventionwith urethane and then exposed to a iodine/potassium iodine solution.Fabric treated in such a way exhibits a wide spectrum of antimicrobialactivity. The iodine treated fabric has the further advantage of being"recharged" by exposing the fabric to an iodine solution. Thus, such anarticle, for example, a fabric insert in an incontinent brief, can bereused simply by washing the insert and then exposing the fabric insertto iodine. Thus, medical/surgical garments can be made into disposable,reusable, rechargeable, antimicrobial protective products. Theseproducts include crotch pads, bandages, surgical gowns and surgical gownwebs, wound coverings, cast interliners, blankets wall coverings,upholstery, surgical drapes and patient gowns.

It is to be understood that the present invention includes theincorporation of other antimicrobial agents, including antifungalagents, antibacterial agents, anti viral agents and antiparasiticagents. Examples of antimicrobial agents that can be used in the presentinvention include, but are not limited to isoniazid, ethambutol,pyrazinamide, streptomycin, clofazimine, rifabutin, fluoroquinolones,ofloxacin, sparfloxacin, rifampin, azithromycin, clarithromycin,fluoroquinolones, dapsone, tetracycline, doxycyline, erythromycin,ciprofloxacin, doxycycline, ampicillin, amphotericin B, ketoconazole,fluconazole, pyrimethamine, sulfadiazine, clindamycin, lincomycin,azithromycin, clarithromycin, pentamidine, atovaquone, paromomycin,diclazaril, acyclovir, trifluorouridine, foscarnet, and ganciclovir.

It is to be understood that the antimicrobial agent can be incorporatedinto the polymer so that the agent is released over a period of time. Inthis way, the barrier web retains its ability to kill or inhibitmicroorganisms over a long period of time.

Webs manufactured according to the present invention that haveantimicrobial molecules in the surfaces can be used to produce a widevariety of articles of manufacture. For example, garments made from thebarrier webs can be made that fit over the clothes of a health careworker. These garments can be gowns or coats or can be wide mesh websthat are capable of preventing blood or other body fluids fromsplattering when they are splashed on the health care worker. If thegarment or mesh has a disinfectant or an antimicrobial agentincorporated into the silicone surface, the garment will not onlyprevent the splattering of blood from a patient but, at the same time,kill or inhibit the growth of infectious organisms that might reside inthe blood or body fluid of the patient.

Another product that can be manufactured using the barrier websaccording to the present invention are sterile filtration masks. Usingthe enhanced surface chemistries described herein, masks can be madefrom the barrier webs that can be used by the worker that may be incontact with potentially dangerous microorganisms. These masks willprevent the transmission of the microorganism prior to contact with theskin or mouth and, if the polymer has an antimicrobial agentincorporated therein, the microorganisms will be inhibited or killed.

The present invention also includes webs with polymers applied theretoaccording to the present invention wherein the polymers have proteinsincorporated into the polymer before application to the fabric. Forexample, a 10,000 Dalton β pleated sheet protein such as Crosilk (Croda,Inc., N.Y., N.Y.) The liquid silicone composition can be comprised ofpolysiloxane polymers containing reactive vinyl carbon to carbon double,along with a platinum catalyst, appropriate fillers and an organosilicone hydrogen compound. The crosslinking cure occurs by a platinumcatalyzed hydrosilation reaction whereby the organosilicone hydrogencompound, which is difunctional, adds across the vinyl double bonds oftwo different polysiloxanes. The incorporation of "Crosilk" protein intothe silicone composition is followed by the impregnation of a fabricwith the mixture, and the silicone is heat cured to crosslink thesystem.

Although not wanting to be bound by the following hypothesis, it isbelieved that the protein is attached to the silicone by a reactionsimilar to the hydrosilation reaction which is also occurring. Additionof proteins with different tertiary or quaternary configurations willimpart different physical characteristics to the fabric being treated.

Another aspect of the present invention is the use of the webs treatedaccording to the present invention in the preparation of bioactivesurfaces. This includes the incorporation of antibodies, antigens,enzymes, or other bioactive molecules into the polymer to be applied tothe fabric, or other surface thereby forming a surface with thebioactive molecule attached thereto. A major advantage of this aspect ofthe present invention includes the fact that because the bioactivemolecule is incorporated directly into the surface at a highconcentration, more bioactive molecule can be exposed to the reactivemedium. This results in a higher reaction rate. This would result in amuch higher signal in, for example, a diagnostic kit utilizing specificantibodies. According to the present invention, the active site of thebioactive molecules can be oriented toward the surface of the fabric (orfiber comprising the fabric) thereby further increasing the bindingactivity or other reaction activity depending upon the bioactivemolecule that is being incorporated into the film.

The present invention can be used to manufacture barrier webs that willnot only provide a physical barrier to microorganisms, but will alsoprovide surfaces that will specifically bind particularly dangerousmicroorganisms such as the human immunodefficiency virus (HIV) or Ebolavirus. Combinations of additives or modifiers are also contemplated aspart of the present invention. For example, antibodies that are specificfor HIV can be incorporated into the polymer surface along with anantimicrobial or disinfectant agent thereby giving the surface theability to specifically bind the HIV and, at the same time, neutralizethe virus through the action of the antimicrobial or disinfectant agent.This is particularly important when working with patients which areknown to be infected with the virus.

Because the present invention lends itself to the formation of bioactivesurfaces, i.e., surfaces with biologically active agents thereon, thebarrier webs are excellent supports for diagnostic applications.

Various assay methods, including but not limited to immunoassays, may beemployed using the bioactive surfaces according to the present inventionto measure the level of an analyte physically present in body fluids orother fluids by use of one or more binding agents such as antibodies.The following techniques can also be used to measure analytes in otherfluids including industrial waste fluids and the like. The methods canalso be adapted to isolate and purify particles from a suspension ofdifferent particles. For example, the present invention can be used toisolate and purify a specific cell population such as stem cells usingthe CD34 antibody incorporated into the barrier web. The following areillustrative, but not limiting, examples of such assay methods.

A first or direct method includes reacting a fluid sample thought tocontain an analyte with a conjugate of a detectable marker or label andan antibody specific to an antigenic site on the analyte molecule tocause formation of antigen antibody complexes. The quantity of theanalyte contained in the sample can be determined by measuring theextent of reactivity of the antibody to the analyte by standard signaldetection techniques which would be dependent upon the type of labelused, as discussed more fully below. In general the analyte-antibodycomplexes are separated from the unbound assay components and then thecomplexes are qualitatively and/or quantitatively analyzed.

As a variation of the first or direct assay method rather thanconjugating the marker directly to the anti-analyte antibody, the markercan instead be conjugated to a suitable, specific binding partner of theanti-analyte antibody. The binding partner may be a monoclonal orpolyclonal antibody directed at a unique determinant site on theanti-analyte antibody or an anti-immunoglobulin specific for theanti-analyte antibody. In this assay method, the secondary antibodyadvantageously may be of the type which is more readily conjugated to alabel. Also, use of the secondary antibody avoids the possibility thatconjugation of the marker to the anti-analyte antibody may adverselyaffect the affinity of the anti-analyte antibody. Further, the secondaryantibody can be of a polyclonal nature, which generally is easier toisolate than are monoclonal antibodies. In addition, use of a secondaryantibody directed to the anti-analyte antibody may result in largercomplexes which are more easily separated from uncomplexed components ofthe assay.

Both the presence and quantity of the analyte in a sample also may beanalyzed with a competitive immunoassay. In this type of assay, a knownamount of a anti-analyte antibody and a known amount of labeled analyteare incubated with a sample to be assayed. Since the antibody does notfavor either the labeled or unlabeled analyte, the antibody binds to thelabeled and unlabeled analyte in proportion to their relative amountspresent. Thereafter, the bound components of the assay, analyte-antibodyand labeled analyte-antibody complexes, are removed from free orunreacted components and then the extent of binding measured by thestandard techniques, discussed below. In this type of competitive assaysystem, a specific concentration of anti-analyte antibody is employed.Preferably, a dilution of analyte antibody is chosen so that theantibody binds to approximately 50% of the labeled antigen. This resultsin a bound-to-free ratio of the elements of approximately 1:1. It is tobe understood, however, that other dilutions of anti-analyte antibodymay be chosen without departing from the scope or spirit of the presentinvention.

In the foregoing competitive assay, prior to the assaying of aparticular sample, varying amounts of unlabeled analyte are incubatedwith a fixed quantity of labeled analyte and a fixed quantity of theanti-analyte antibody. The extent to which the labeled analyte bindswith the anti-analyte antibody is then measured for each samplecontaining the known amount of unlabeled analyte. From the results ofthese measurements, a standard curve may be prepared depicting theextent of binding between the labeled analyte and the antibody in thepresence of a quantity of unlabeled analyte. Then, when a particularsample containing an unknown amount of unlabeled analyte is assayed, theconcentration of the unlabeled analyte in the sample may be determinedfrom the standard curve once the extent of which the labeled analytebinds to the anti-analyte antibody is measured.

The present invention also contemplates use of the novel bioactivesurfaces on the barrier webs with the antibodies prepared and isolatedin double determinant immunoassays for measuring the level of analyte inbody fluid. In this type of assay, a first antibody reactive with aunique recognition site on the analyte molecule is placed in contactwith the sample to be tested. If analyte is present in the sample, itbinds specifically to the first antibody molecules. After the unboundanalyte is separated from the bound analyte, for instance by washing,the first antibody-analyte complex is contacted with a second antibodyreactive with a different recognition site on the trapped analytemolecule, which second antibody attaches to the bound analyte in adose-dependent fashion. It will be appreciated that in the doubledeterminant assay it is important that the two anti-analyte antibodiesare reactive to unrelated epitopes on the analyte molecule therebyavoiding stereotypic effects caused by the binding of the two antibodiesto the analyte molecule.

The second antibody may be labeled so that the extent of binding of thesecond antibody to the analyte can be measured by standard procedures.Rather than labeling the second antibody directly, a binding partner forthe second antibody which is conjugated to a marker may be employed. Thebinding partner may be a secondary antibody that is specific for thesecond antibody. As noted above, by avoiding the necessity of labelingan anti-analyte antibody, the possibility that the labeling may cause achange in the affinity of the antibody is eliminated. Moreover, theantibody employed as the secondary antibody may be chosen on the basisof desirable characteristics, such as ease of labeling, ability togenerate and ease of separating bound from unbound antibody. It will beappreciated that in the double determinant assay by using a firstantibody to trap the analyte molecule and then a second antibody todetect the molecule, a very sensitive immunoassay results.

Although various types of immunoassays have been discussed above, itwill be appreciated that numerous variations of the assays may beemployed as well as other types of immunoassays. For instance, thelabeled or unlabeled analyte protein could be replaced with a suitablylabeled analyte specific peptide with which the antibody(ies) is (are)reactive.

The present invention contemplates the use of various types of insolubleseparation barrier webs made according to the present invention inconjunction with the above immunoassays. For example, in the competitiveassay, the anti-analyte antibody, may be covalently or noncovalentlybound to the barrier web. The same is true for the anti-analyte antibodyemployed in the double determinant assay. The barrier web may becomposed of the plastic or glass microtiter plate wells or otherreaction vessels in which the assay itself is carried out.Alternatively, the support may be in the form of a plastic, cellulose orglass fiber disk, plate or strip which is dipped into or otherwiseplaced in contact with the analyte-containing fluid sample. Barrier websupports may be of various compositions, such as polyvinyl,polyacrylamide, polystyrene, acrylamide, polypropylene or polycarbonate.Also, the support may be composed of matrices of various configurations,such as a mesh material or beads of spherical or other shapes which arecontained in a reaction vessel. Various activating compounds may beemployed to covalently bind the antibody to the barrier web, which iswell known in the art. Such activating agents may include, for instance,cyanogen bromide (CNBr), carbodiimide, glutaraldehyde, polyethylenegycoland tannic acid.

Because the porosity of the barrier webs of the present invention can becontrolled, the barrier webs are ideally suited as size exclusionfilters. For example, if one desires to exclude microorganisms from asolution that are over a certain size, one can select a barrier web withpore sizes that are below the desired exclusion size. One can then pouror force the solution through the barrier web thereby trappingmicroorganisms that are greater than the pore size of the barrier web.One can optionally include a barrier web with a bioactive surface tofurther control what particles can pass through the web.

The assays of the present invention are preferably conducted in a liquidmedium at moderate pH and temperature. The medium may be of an aqueousnature; however, ideally it is composed of a buffered salt solutionmedia, such as 0.1 molar ("M") Tris buffered saline containing 3% ofalbumin (ovine. bovine or human). Preferably, the pH of the medium is inthe range of about 5-10 and, more preferably. in the range of about 6-9,and ideally about 7.2. The pH is chosen to facilitate specific bindingbetween the analyte and the antibody or antibodies, while avoiding anysignificant negative effect on the signal produced by the markerconjugated to the antibody. To achieve the desired pH and maintain itduring the assay procedure various buffers may be employed. Examples ofsuitable buffers include, for example,N-2-hydroxy-ethylpiperazine-N-2-ethane-sulfonic acid ("HEPES"), Tris,borate, phosphate, carbonate and barbital.

As noted above, the present assay may include one or more incubationprocedures. For example. in the double determinant assay method, thesample of interest is incubated with a first anti-analyte antibody whichhas been bound to an insoluble support. Thereafter, in a secondprocedure, the first antibody analyte complex is incubated with a secondanti-analyte antibody. The length of the incubation period and theincubation temperature will depend, to a large extent, on the bindingrate of the analyte to the antibody and on the type of label employed.The incubation periods may range from a few minutes to several hours,typically from about 5 minutes to up to 24 hours. The incubationtemperatures will generally range from about 1° C. to 32° C., andideally approximately 4° C.

In the present invention, the anti-analyte antibody itself or aseparate, secondary antibody directed to the anti-analyte antibody maybe conjugated with a detectable marker to produce a signal related tothe presence of analyte. In the test sample, the detectable marker canbe selected from among fluorophores, colored dyes, enzymes,chromophores, coenzymes, chemilluminescent materials, enzyme inhibitors,paramagnetic materials such as gadolinium, ferritins and radionuclidesthat are known in the art. Illustrative, but non-limiting examples ofparticular enzymes which might be employed include horseradishperoxidase, alkaline phosphatase, and β-galactosidase. Illustrativeexamples of colored dyes include, but are not limited to, amido blackand eosin. Illustrative fluorescent compounds include, withoutlimitation, fluorescein, isothiocyanate, dansyl, propidium iodine aswell as phycophores, such as phycoerythrin.

The detectable marker may also be composed of a radioactive isotope. Thetechnique used for labeling the antibody varies with the type ofradioactive isotope employed. For instance, labeling can be accomplishedby replacing one of the atoms of the antibody molecule with acorresponding radioactive isotope. As a specific example, a hydrogenatom could be replaced with tritium (³ H); a carbon atom could bereplaced by carbon-14 (¹⁴ C); or, a strontium atom replaced withstrontium-38 (³⁸ Sr). In an alternative labeling process, rather thanreplacing the atoms of the antibody with a radioactive isotope, anisotope may be added to the antibody molecule. Such radioactive isotopesin common use include, but are not limited to, iodine-125 (¹²⁵ I) andiron 59 (⁵⁹ Fe).

It will be appreciated that the particular marker or label employeddepends on various factors, such as the particular type of immunoassaybeing used and the biological and biochemical characteristics of theanti-analyte antibody or secondary antibody being labeled. Whatever typeof marker is employed, it, of course, should not cause any significantchange in the specificity between the labeled antibody and its specificrecognition site.

After each of the various incubation steps in the assay of the presentinvention, the complexed or bound components of the assay typically areseparated from the unbound components, noncomplex analyte, excessanti-analyte antibodies and secondary antibodies. The methods mayinclude simply washing with, for instance, a saline solution alone orcombined with centrifugation. The separation may includeultrafiltration, dialysis or salt precipitation. Other separationprocedures may be based on differential biochemical migration, forinstance, chromatography, electrophoresis, chromatoelectrophoresis andgel filtration. The particular type of separation method(s) employedwill depend upon the specific immunoassay procedure used and thecharacteristics of the assay reagents.

Diagnostic Kit

The present invention also includes a diagnostic kit for carrying outthe analyte assays disclosed above to detect the presence of an analyte.In its most basic form, the kit for measuring the analyte comprises acontainer and a web that has been treated with a curable thixotropicpolymer composition with molecules that bind the analyte positionedtherein.

The particular components of the kit can correspond to the particularassay procedure being employed. In perhaps its simplest embodiment, thediagnostic kit may include a polyclonal or monoclonal antibody directedagainst analyte which has been conjugated with a suitable marker capableof producing a detectable signal. To carry out the assay, the testsample is placed in contact with the antibody-marker conjugate.Thereafter, the complexed components are separated from free componentsof the assay and then the signal produced by the marker is detected andquantified in either the bound or free components of the immunoassayreaction. As noted above, the assay components include an insolublematrix comprising the barrier web with the suitable binding agentincorporated therein, buffers to maintain the desired pH of theimmunoassay reaction and binding media to dilute the fluid sample. Thekit may also include reagents required for the marker to produce adetectable signal, such as an appropriate enzyme reagent for ELISAassay, or agents to enhance the detectable signal.

In another illustrative, but nonlimiting example, the diagnostic kit mayinclude a polyclonal or monoclonal antibody directed against analyte anda secondary antibody directed against the anti-analyte antibody, whichsecond antibody is conjugated to a suitable marker capable of producinga detectable signal. As in the embodiment of the assay kit discussedabove, this kit embodiment also may include other additional components.To carry out the assay, a test sample is placed in contact with theanti-analyte antibody and then the complexed components separated fromthe free components using the barrier web of the present invention as asolid support with the appropriate binding agent thereon. Thereafter,the complex components are placed in contact with the labeled secondaryantibody which specifically couples with the anti-analyte antibody boundto the analyte. After the unbound secondary antibody is separated fromthe complexed components of the assay, the signal produced by the labelis measured in either the bound or free components of the assayreaction.

In a further illustrative embodiment of the present invention, thediagnostic kit may include the components necessary to carry out thedouble determinant assay procedure described above. This particular kitcomposition includes first and second antibodies directed againstseparate determinant sites on the analyte molecule. Preferably, thefirst antibody is covalently or noncovalently coupled to a barrier webmade according to the present invention. The second anti-analyteantibody may be conjugated with a suitable marker capable of producing adetectable signal or alternatively a third labeled secondary antibodydirected against the second anti-analyte antibody may be employed.Again, as noted above, the kit may include various additional componentsto optimize or facilitate the assay procedure.

The present invention also provides substrates for growing cells such aprocaryote or eucaryote cells. The substrates comprise webs that havevarious growth factors incorporated into the polymer surface as definedherein and in copending patent applications. These webs can be placed incontainers, such as conventional fermenters with the appropriatenutrient solutions thereon. Cells can be seeded on the webs and allowedto grow at the appropriate temperature. The cells or the productsproduced by the cells can be easily harvested from the fermentors.

This invention is further illustrated by the following examples, whichare not to be construed in any way as imposing limitations upon thescope thereof. On the contrary, it is to be clearly understood thatresort may be had to various other embodiments, modifications, andequivalents thereof, which, after reading the description herein, maysuggest themselves to those skilled in the art without departing fromthe spirit of the present invention and/or the scope of the appendedclaims.

EXAMPLE 1

Liquid Silicone Polymer Preparation

100 parts by weight of the curable liquid silicone polymer availablecommercially from Mobay as "Silopren® LSR 2530" was mixed in a 1:1ratio, as recommended by the manufacturer. A Hockmayer F dispersionblade at low torque and high shear was used to do the mixing. To thismixture were added 5 parts by weight of BSF "Uvinul 400" and 5/10 partsby weight Dow Corning 7127 accelerator, believed to be a polysiloxanebut containing an undisclosed active accelerated ingredient.

EXAMPLES 2-19

Liquid Silicone Polymer Preparation with One or More Modifiers

The procedure of Example 1 was repeated with various other commerciallyavailable curable viscous liquid silicone polymer compositions. To thisproduct system a substituted benzophenone and other additives areoptionally added, the results of which are shown in Table III. Theseexamples illustrate that more than one additive can be combined in thepractice of this invention. All parts are by weight.

                                      TABLE III                                   __________________________________________________________________________    Illustrative Silicone Resin Compositions                                                      MIXTURE  SUBSTITUTED                                                          RATIO OF SUBSTITUTED                                          EXAMPLE                                                                             STARTING  PACKAGED BENZOPHENONE                                                                            OTHER ADDITIVES                            NO.   SILICONE RESIN                                                                          COMPONENTS.sup.(1)                                                                     NAME  PARTS                                                                             NAME    PARTS                              __________________________________________________________________________    1     Silopren ® LSR 2530                                                                 1:1      Uvinul 400                                                                          5   7127 Accelerator                                                                      5/10                               2     Silastic ® 595 LSR                                                                  1:1      Uvinul 400                                                                          5   Syl-Off ® 7611.sup.(2)                                                            50                                 3     SLE 5100  10:1     Uvinul 400                                                                          5   Sylox ® 2.sup.(3)                                                                 8                                        Ligquid BC-10                                                                           1:1                                                           4     Silopren ® LSR 2530                                                                 1:1      Uvinul 400                                                                          5   Hydral ® 710.sup.(4)                                                              10                                 5     Silopren ® LSR 2530                                                                 1:1      Uvinul 400                                                                          5   Silopren ® LSR                                                                    1                                                                     Z3042.sup.(5)                              6     SLE 5500  10:1     Uvinul 400                                                                          5                                              7     Silopren ® LSR 2540                                                                 1:1      Uvinul 400                                                                          5                                              8     SLE 5300  10:1     Uvinul 400                                                                          5                                              9     SLE 5106  10:1     Uvinul 400                                                                          5                                              10    Silopren ® LSR 2530                                                                 1:1      Uvinul 400                                                                          5   Flattening Agent                                                                      4                                                                     OK412 ®.sup.(6)                        11    Silopren ® LSR 2530                                                                 1:1      Uvinul 400                                                                          5   Nalco.sup.(5) 1SJ-612                                                                 50                                                                    Colloidal                                                                     Silica.sup.(7)                             12    Silopren ® LSR 2530                                                                 1:1      Uvinul 400                                                                          5   Nalco ® 1SJ-614                                                           Colloidal                                                                     Alumina.sup.(8)                            13    Silastic ® 595 LSR                                                                  1:1      Uvinul 400                                                                          5   200 Fluid.sup.(7)                                                                      7                                 14    Silopren ® LSR 2530                                                                 1:1      Uvinul 400                                                                          5                                              15    Silastic ® 595 LSR                                                                  1:1      Uvinul 400                                                                          5   Zepel ® 7040.sup.(10)                                                             3                                  16    Silastic ® 595 LSR                                                                  1:1      Uvinul 400                                                                          5   Zonyl ® UR.sup.(11)                                                               1/10                               17    Silastic ® 595 LSR                                                                  1:1      Uvinul 400                                                                          5   Zonyl ® FSN-                                                                      1/10                                                                  100.sup.(12)                               18    Silopren ® LSR 2530                                                                 1:1      Uvinul 400                                                                          5    DLX-600 ®.sup.(13)                                                               5                                  19    Silopren ® LSR 2530                                                                 1:1      Uvinul 400                                                                          5   TE-3608 ®.sup.(14)                                                                5                                  __________________________________________________________________________     Table II Footnotes:                                                           .sup.(1) Ratio listed is that recommended by the manufacturer.                .sup.(2) Syloff ® (registered trademark of Dow Corning) is a              crosslinker.                                                                  .sup.(3) Sylox ® 2 (registered trademark of W. R. Grace Co.) is a         synthetic amorphous silica.                                                   .sup.(4) Hydral ® 710 (registered trademark of Aloca) is hydrated         aluminum oxide.                                                               .sup.(5) Silopren ® LSR Z/3042 (registered trademark of Mobay) is a       silicone primer (bonding agent) mixture.                                      .sup.(6) Flattening Agent OK412 ® (registered Trademark of Degussa        Corp.) is a wax coated silicon dioxide.                                       .sup.(7) Nalco ® 1SJ612 Colloidal Silica (registered trademark of         Nalco Chemical Company) is an aqueous solution of silica and alumina.         .sup.(8) Nalco ® 1SJ614 Colloidal Alumina (registered trademark of        Nalco Chemical Company) is an aqueous colloidal alumina dispersion.           .sup.(9) 200 Fluid (registered trademark of Dow Corning) is a 100             centistoke viscosity dimethylpolysiloxane.                                    .sup.(10) Zepel ® 7040 (registered trademark of duPont) is a nonionic     fluoropolymer.                                                                .sup.(11) Zonyl ® UR (registered trademark of duPont) is an anionic       fluorosurfactant.                                                             .sup.(12) Zonyl ® FSN100 (registered trademark of duPont) is a            nonionic fluorosurfactant.                                                    .sup.(13) DLX6000 ® (registered trademark od duPont) is                   polytetrafluoroethylene micropowder.                                          .sup.(14) TE3608 ® (registered trademark of duPont) is a                  polytetrafluoroethylene micropowder.                                     

EXAMPLE 20

Internally Coated Fiber Encapsulated, Interstice Filled FabricPreparation

A complete, stepwise, application of the inventive method in theproduction of an encapsulated fiber fabric was as follows.

The selected base fabric was TACTEL® (gold color) #612071 available fromICI Americas, Inc. This fabric was 100% woven nylon. If desired, thisand other fabrics may be calendered to modify surface texture, geometryand porosity. The fabric was weighed and measured. Its initial weight is3.1 ounces per square yard. Its thickness equals 9 mils. The fabric wasnext washed with detergent, rinsed thoroughly, and hung to air dry. Thefabric was soaked in water, wrung dry, and weighed. The water retainedwas equal to 0.8 g water/g fabric. The fabric was then treated with awater repellent fluorochemical, a 2% solution by weight of Zepel® 7040.In order to do so the fabric must be soaked in a 2.5% solution of Zepel®water-repellent chemical in distilled water. This was because: ##EQU2##

The treated fabric was then run through a wringer and air dried. Next,the fabric was heated in an oven for 1 minute at 350°. This heatingsinters the water repellent fluorochemical. The fabric with itsfluorochemical residue is then run as in the FIG. 7 embodiment. Thesilicone polymer composition is applied at 1.0 oz./sq. yd. The polymercomposition is GE 6108 A/B in a 1:1 ratio and can be considered to be aviscoelastic liquid that flows only under the shear forces resultingfrom the pressured controlled placement. The polymer composition isbelieved to return very substantially to its original viscous conditionalmost immediately upon release of the pressure. The polymer compositionwas believed to flow a short distance within the matrix of the fabricduring the short time that it was, because of pressure shearing forces,of lowered viscosity. Therefore, a number of "flows" may be usefullygenerated with multiple blades in order to properly distribute thepolymer composition in its preferred position substantiallyencapsulating the surfaces of the fabric's fibers.

Finally, the treated fabric was run through a line oven, ofapproximately 10 yards in length, at 4-6 yards per minute, and was curedat 325-350° F. It then passed through a series of idler rollers and isrolled up on a take-up roll, completing the tension zone. The resultantfabric has a non-tacky thin film of silicone that was internally coatedto form a fiber encapsulated, interstice-filled layer in the fabric.

EXAMPLE 21

Evaluation of Fiber Encapsulated Fabric Properties

The test results of the original versus the produced fiber encapsulatedfabric of Example 20 were as follows:

                  TABLE IV                                                        ______________________________________                                        FABRIC        ORIGINAL FABRIC                                                                             ENCAPSULATED                                      ______________________________________                                        Spray Rating (1)                                                                            20            100 (reverse = 100)                               Rain Test (2) Fail          Pass                                              Abrasion Test (cycles) (3)                                                                  1,800         3,200                                             Moisture Penetration (4)                                                                    Saturated     0.0 g                                             Hydrostatic Resistance (psi)                                                                1             2                                                 (5)                                                                           MVTR (g/M.sup.2 /day)* (6)                                                                  4,414         2,362                                             Weight (oz/yd.sup.2)                                                                        3.1           4.1                                               ______________________________________                                         Amount Impregnated = 1.4 oz/yd.sup.2                                          *Environmental chamber at 104° F. and 74% humidity.               

                  TABLE V                                                         ______________________________________                                        LAUNDERING TEST (7)                                                                            TIMES WASHED                                                 (Spray Ratings)  Initial                                                                              5× 10×                                                                          15×                               ______________________________________                                        Impregnated Side 100    90       90   90                                      Reverse Side     100    90       90   90                                      Unimpregnated Treated Fabric                                                                   100    80       80   40                                      ______________________________________                                    

Accelerated Weathering Test (8)

Samples placed in QUV weatherometer for 72 hours.

Original=7

Impregnated Side=9

Reverse Side=8

(1) The spray test was conducted in accordance with AATCC 22-1974. Itmeasures water repellency of a fabric sample on a scale of 0-100, with areading of 100 designating a completely water repellent fabric.

(2) The rain test was conducted in accordance with AATCC 35-1985. Itmeasures resistance of a fabric sample to penetration of water understatic pressure from a shower head of 3 feet/5 minutes. A fabric isstormproof when less than 1.0 gram of water is absorbed by astandardized blotter used in the test.

(3) The abrasion test was conducted in accordance with Federal TestMethod Standard 191 A, Method 5306. Abrasion resistance is measured bymounting a fabric sample on a Taber Abraser Model 174 and measuring thenumber of cycles before the fabric begins tearing apart.

(4) The moisture penetration test was conducted in accordance with AATCC70-1994. It measures the resistance of fabrics to wetting by water, bymeasuring the penetration of water into, but not through, the fabric.

(5) The hydrostatic resistance test was conducted in accord with FederalTest Method Standard 191A, Method 5512. The test measures a fabricsamples' resistance to water under pressure using the Mullen's BurstTest methods and apparatus. Test results are expressed in pounds persquare inch at which water beads penetrate the fabric.

(6) The moisture vapor transmission (MVTR) test was conducted inaccordance with ASTM E96-B. The test measures the amount of moisturevapor passing through a fabric sample in a controlled environment duringa 24 hour period. The obtained MVTR figure is expressed in grams ofwater/square meter of surface/24 hour day. The environmental chamber washeld at 104° F. and 47% humidity.

(7) A laundering test of the conventional household type was performed.Fabric samples were washed with Tide® detergent. There was no drying. Aspray test was subsequently carried out after each wash to determine theeffect of the washing.

(8) The accelerated weathering test was conducted in accordance withASTM G-53. Samples of original and impregnated fabrics were placed inthe weatherometer of QUV Company and results were compared. (Allreadings were based on a graduated color scale of 0-20; 10 designatedthe original color, while 0 designated a white out.)

EXAMPLE 22

Iodine As A Biocidal And Antimicrobial Agent with Polyurethane as aReactive Site

This example demonstrates the preparation of a biocidal orself-sterilizing web. Polyurethane, Sancor® 898 in a latex form, wasmixed with silicone polymer, Dow Corning 2962 (Parts A & B 50:50) in theratios of 0%, 5%, 10%, 15% and 100%, by weight respectively. Variousfabric webs such as Burlington 4040, 4045 and Versatec, were treatedwith 15-20% weight add-on of the above polymer mixtures in accordancewith the practice of this invention. The fabrics were cured at 350° F.(176° C.) for 26 seconds. The treated fabrics were dipped in an iodinesolution bath containing 2% iodine in a 2.4% KI solution or 2% iodine inan ethanol solution for 10-30 seconds at room temperature and rinsed ina freshly-distilled water bath until no free iodine came off. Theiodine/silicone/urethane-treated fabrics were then air dried andobserved to be yellowish on the silicone/urethane treated side,indicating the presence of iodine.

A culture of XL Blue E. Coli was prepared in a refrigerated LB Agar andgrown for 9 hours. Two drops of cultured XL Blue E. Coli were added tofour streaked LB Agar plates and spread with a bent sterile 1 mLpipette. The iodine/silicone/urethane-treated fabric web samples wereplaced (treated side down) on the LB Agar plates and grown in anincubator at 37° C. After 24 hours, an area of growth inhibition wasobserved for all samples, which is indicative of the active killingsites for each piece of treated fabric. The treated fabric was thenwashed, charged with free iodine and then re-tested for antimicrobialactivity. The growth of bacteria was inhibited both under and around thetreated fabric samples.

A latex web, instead of a fabric web, when treated withsilicone/polyurethane, also shows the ability to bind free iodine. Afterdipping in 2% iodine ethanol solution, theiodine/silicone/urethane-treated latex web samples were placed on LBAgar plates. Again, bacteria growth inhibition was observed both underand around the samples.

EXAMPLE 23

Protein Additives As Hand Altering Agents, Surface Chemistry ModifiersAnd Antibody Binding Sites

The proteins used in the practice of this invention were"Silk-Like-Protein 3 (SLP-3)," produced by Protein Polymers, Inc. (SanDiego, Calif.) and "Crosilk," produced by Croda, Inc. (New York, N.Y.).Crosilk is a 10,000 molecular weight protein made by hydrolyzing silk,and is comprised of 17 different amino acid segments, ranging in percentweight of 0.1 % to 20.3%. The silicones used herein are Mobay Silopren®LSP 2530 and Dow Corning Silastic® LSR 2303. The webs used herein areEggplant Supplex, Black Cordura, and a 48% Nylon/52% Cotton blend.

Prior to mixing the protein with the silicone polymer, the dimensions ofthe protein particles need to be adjusted to a suitable particle sizesuch as 0-2 microns in length and 0-2 microns in diameter. This can beaccomplished by grinding the protein particles with a small amount ofsilicone polymer, in a ball mill in a solvent such as xylene. Thesolvent is used to lower the viscosity of the silicone polymercomposition in the ball mill. Generally, the mixture in the ball mill iscomposed of about 5% SLP-3, 50% silicone polymer composition and about45% of xylene. The grinding of protein can also be done without asolvent. After grinding, additional silicone polymer composition wasadded to the protein/silicone mixture to produce a mixture containingabout 2.5% by weight protein. The xylene solvent evaporates during thisprocess. The final protein/silicone mixture was then applied to the websin accordance with the practice of this invention. The treated web wascured at 320° F. for 2 minutes. Any xylene residue remaining evaporatesduring the final curing stage. The resulting webs showed improved handfeel (tactility), moisture vapor permeability, and surface exposure asshown by further binding tests with antibodies. The permeability testresults are summarized in the following table.

                  TABLE VI                                                        ______________________________________                                        MVTR Results of Webs Treated with SLP-3 Protein Additive                      Materials       MVTR (g/m.sup.2 · day)                                                            Breathability                                    ______________________________________                                        Eggplant         964         --                                               LSP2530 w/SLP-3 1504         156%                                             Eggplant + DWR  2089         --                                               LSP2530 w/SLP-3 2718         130%                                             Black Cordura   3387         --                                               LSP 2303 w/SLP-3                                                                              4115         122%                                             Black Cordura   2823         --                                               LSP 2530 w/SLP-3                                                                              9799         347%                                             48% Nylon/52% Cotton                                                                          4076         --                                               LSP 2530 w/1% SLP-3                                                                           4203         103%                                             LSP 2530 w/5% SLP-3                                                                           7133         175%                                             ______________________________________                                         DWR  Durable Water Repellent such as a fluorochemical composition.       

Each row shows both the control sample (without polymer and withoutSLP-3 protein) and a treated web sample with the polymer and the SLP-3protein additive. The moisture vapor transport rate increased with theSLP-3 protein. This shows that the protein assists in the transport ofmoisture vapor.

Samples of webs treated with the SLP-3 protein additive were exposed tothe anti-SLP-3 antibody, washed, then exposed to radioactively labelled"protein A." The sample then was washed, and analyzed for theradioactively labeled "protein A." Protein A is a bacterial proteinwhich specifically binds to antibodies. The tested samples contained 1%and 5% by weight SLP-3 protein and then antibodies were allowed to bind.The control samples contained the same amount of SLP-3 protein but noanti-SLP-3 antibodies. The samples containing more SLP-3 protein showedlarger amounts of bound antibodies. This result shows that the SLP-3protein was surface exposed and created a binding site for antibodies.

Crosilk was used as an additive in Mobay LSP 1530 silicone polymer. Thismixture was applied to webs such as Arthur Kahn Blue Cotton, Arthur KahnWhite Tactal and Patagonia Red Supplex. All webs were cured two minutesin an oven at 320° F. The presence of the hydrolyzed silk did notinhibit the cure of the silicone polymer. The treated webs showed aslightly improved feel and no real appreciable difference in the MVTRresults of the fabric. This result shows that although various proteinscan be utilized, the same functionality does not appear. Some proteinscan be used specifically for binding antibodies, some for altering the"feel" of the fabric, some for modifying the surface characteristics ofthe polymer and/or web, and some for altering the moisture vaportransport rate.

EXAMPLE 24

Pigments, Dyes and Proteins on Fibers

This example illustrates the addition of pigments, dyes, and proteins topolymers and the application of the polymer compositions onto fibers.The following is a preferred procedure for processing fibers,particularly for use in carpets.

1. Tension a single bundle of fibers across a lab encapsulator. Thisset-up presents a knife-over-air process condition on the carpet fiber.

2. Comb the fibers using a very fine comb to individually isolate thefilaments to prevent them from sticking or spot welding together.

3. Apply the polymer composition with the dye, pigment, or protein mixedinto it, onto the surface of the tensioned fibers.

4. Take semi-dull encapsulating applicator, such as a flex knife, andshear the polymer composition to get a uniform, fully encapsulatedfabric.

5. Once again, comb fibers to individually separate and prevent themfrom sticking together.

6. Pin the comb to one end of the lab encapsulating frame and cure thepolymer composition.

The above process was used to apply a red pigment onto Nylon 6 CF carpetfibers. The polymer composition used was a 50/50 DG2303 mixed with A-50red pigment. Twenty lbs. of tension was applied across the fibers. Theflex knife was pulled across the fibers ten times to shear thin thepolymer composition. The treated fibers were cured for five minutes at320° F. The red pigment appeared uniformly around the fibers whenexamined under a microscope.

The above process was also used to apply a polymer composition and a redpigment onto BASF 70/32 Bright Tri-Lobal Nylon 6 yarn. Seven 14 inchstrands were tensioned at about 10 lbs. The polymer composition was SLC5106 A&B in a 10:1 ratio mixed with 30% weight add-on of silicone red(8010.94 40% pyrazalone-VT). The composition was shear thinned and thencured at 320° F. for five minutes. The red pigment appeared uniformlyaround the fibers when examined under a microscope. This shows theencapsulating aspect of the polymer composition and the ability tointroduce red dyes and pigments around individual fibers.

The above process was also used to apply the SLP-3 Beta silk protein toindividual fibers. The polymer composition used was DC-2303 A&B in a 1:1ratio mixed with 10% by weight of SLP-3 Beta silk protein. The proteinwas ground up in a mill grinder before addition to the polymercomposition. Ten lbs. of tension was applied. The fibers were washedwith warm water and then dried. Six shears were applied with theshearing means on the top and bottom of the fibers. Between shears, theexcess was wiped off. The composition was cured at 320° F. for fiveminutes. The presence of the SLP-3 protein was seen uniformly around thefibers under a microscope.

Additional samples were run using the same procedure, and the resultsare shown in the table below:

                                      TABLE VII                                   __________________________________________________________________________         Product                                                                  Company                                                                            Description                                                                            Obstacles                                                                             Solution                                                                              Process Successes                               __________________________________________________________________________    Shaw 1800 Denier                                                                            Sensitive to                                                                          Add platinum                                                                          Heat set                                                                              Addition of Red Dye                     Industries                                                                         Bulked   heat    Reduce cure heat                                                                      5/5/ shear                                                                            in polymer                                   Polypropylene            Appears to be                                                                         Ran SLC 5106                                 Beige                    encapsulated                                                                          Tried platinum                                                                accelerator                             Shaw 2600 Denier Dull                                                                       Sensitive to                                                                          Add platinum                                                                          Heat Set                                                                              Addition of Red Dye                     Industries                                                                         Polypropylene                                                                          heat    Reduce cure                                                                           Reduce heat                                                                           Ran SLC 5106                                 Blue     Colored Fiber                                                                         Use DC2303                                                                            cure    Success with                                                          Appears to be                                                                         accelerator                                                           encapsulated                                                                          Appears to                                                                    encapsulate                             Shaw 3050 Denier                                                                            Multiple                                                                              Use all polymers                                                                      Heat set                                                                              Reduces shrinking                       Industries                                                                         Nylon 6 Fiber                                                                          Fibers  High shear                                                                            5/5 shears                                                                            Tried all polymers                           Bulked Multicolor                                                                      Fiber Welding                                                                         Cure relaxed                                                                          Add     Isolated best process                                 Bulked  High speed shear                                                                      accelerators                                                                          35 mm picture taken                                   Tri-Lobal Fiber Appears to be                                                                         Tired ceramic acrylic                                                 encapsulated                                    BASF 70/32 Brt. Tri-                                                                        Small   High tension                                                                          6/6 shear                                                                             Tried SLC5106                           Corp.                                                                              Lobal Nylon 6 for                                                                      Filament                                                                              High shear                                                                            Appears to be                                                                         Tried Red Dye in                             Textiles Tightly spun                                                                          Water clean                                                                           encapsulated                                                                          polymer                                               Residual                                                                              High speed                                                            Tri-Lobal                                                       BASF Nylon 6 Unbulked                                                                       8800 Denier                                                                           Alt. Process                                                                          6/6 shears                                                                            Tried all polymers                      Corp.                                                                              8800 Denier CF                                                                         Fiber Welding                                                                         Splitting up fiber                                                                    Appears to                                                                            Red Dye in polymer                           Yarn White                                                                             Residuals                                                                             Water wash                                                                            encapsulate                                                                           Picture taken                                                 Solvent wash                                                                          Tried all                                                                             Added accelerators                                                    polymer Trying to process all                                                 Curing process                                                                        fiber                                   DuPont                                                                             Antron Nylon                                                                           Bulked  High Tension                                                                          Heat set                                                                              Red Dye in polymer                           Bulked Fibers                                                                          Faceted Fiber                                                                         High shear                                                                            6/6 shears                                                                            Tried SLC5106                                         Residuals                                                                             6/6 shears                                                                            Appears to                                                                            Add accelerators                                      Fiber Welding                                                                         Heat set                                                                              encapsulate                                                                           Need better flow                                              Cure relax state                                                                      Add Red Dye                                                                           character                                                             Cure relaxed                                                                          Try different polymer                   DuPont                                                                             Bulked Twisted                                                                         Thick Yarn                                                                            High Tension                                                                          10/10 shear                                                                           Shear thinning                               Finished Antron                                                                        Multi-Twist                                                                           High speed                                                                            Shear blade                                                                           Increased bulk                               Carpet Yarn                                                                            Residuals                                                                             High shear                                                                            Add accelerator                                                                       Fiber welding                                         Entanglement                                                                          Alt. polymer                                                                          Tried SLC5106                                                                         Higher speed needed                                                   Red Dye                                         __________________________________________________________________________

EXAMPLE 25

A Flattening Agent as an Additive

In this example, the look of the treat web was flattened by adding anamorphous silica compound labeled OK 412, produced by Degussa, Inc.(Frankfurt, Germany), available through its pigment division inTeterboro, N.J., to the silicone polymer prior to application to theweb. The introduction of this material into the silicone polymer reducedthe glossy look of the final cured silicone composition, allowing theweb to maintain its cotton-like look and hand. The silicone polymer usedherein is Mobay Silopren® LSR 2530. The flattening agent OK 412 wasmixed in the ratio of 80% by weight LSR 2530 A/B, 17% by weight OK 412,and 3% by weight White mineral spirits. The mixture was then applied inaccordance with the practice of this invention, to Milliken Poplin (65%polyester/35% cotton) and Arthur Kahn Dune (100% cotton), respectively.The webs were pre-treated with a 3.5% fluorochemical solution of F31Xdurable water repellant (DWR). The silicon/OK 412 treated webs werecured in an oven at 350° F. for 1.5 minutes. All webs treated with thesilicone/OK 412 mixture showed significant improvement in abrasionresistance while flattening the glossy look and maintaining the feel ofthe web. The test results of the above samples are summarized in thefollowing table:

                  TABLE VIII                                                      ______________________________________                                        Test Results of OK 412 Treated Webs                                           Fabric Materials                                                                            Spray Test                                                                              Rain Test                                                                              Abrasion Test                                ______________________________________                                        Milliken Poplin                                                                             0         saturated                                                                               75 cycles                                   (65% polyester/35% cotton)                                                    LSR 2530      90        0 g      125 cycles                                   w/OK412 + DWR                                                                 Aurthur Kahn Dune                                                                           0         saturated                                                                               75 cycles                                   (100% cotton)                                                                 LSR 2530      90        0 g      150 cycles                                   w/OK412 + DWR                                                                 ______________________________________                                         DWR -- Durable Water Repellent such as a fluorochemical composition.     

Each row shows both the control sample (without polymer and withoutadditives) and a treated web sample with the polymer and the OK 412additive.

EXAMPLE 26

Topical Application of a Flattening Agent

In this example, the look of the treat web was flattened by topicallyapplying an amorphous silica compound labeled OK 412, produced byDegussa, Inc. (Frankfurt, Germany), available through its pigmentdivision in Teterboro, N.J., to the silicone polymer treated web priorto curing. The introduction of this material upon the silicone polymertreated fabric reduced the glossy look and altered the feel of thefabric after curing. The silicone polymer used herein is GE 6108 A:B(1:1).

The fabric was a Navy Blue 3-ply Supplex (100% Nylon). The fabric wasstretched to a tension of 15 Newtons. The polymer was applied and shearthinned into the fabric using a shearing knife. The polymer weightadd-on was approximately 29%. The samples were then sprinkled withOK412. This was done with a fine screen that dispersed the powder uponshaking. The sample was then passed under a nip to force the additiveinto the fabric and into the polymer composition. The sample was curedfor 30 seconds at 350° F. A sutter test was run on the sample and thesample was rinsed with water and dried.

Upon rinsing the fabric the white spots on the navy blue supplexdissappeared. After drying, the spots reappeared, indicating that theadditive adhered to the polymer composition in the fabric. This showsthat a topically applied additive will adhere to the polymer compositionand will retain its functionality.

EXAMPLE 27

Copper Particles as an Additive

This example demonstrates the preparation of a web containing sub microncopper particles. Sub micron copper particles were mixed with siliconepolymer, Dow Corning 2303 (Parts A&B 50:50) in the ratios of 0%, 5%,10%, and 20% by weight respectively. Various fabric webs such asBurlington 4040, 4045 and Versatec, were treated with 15-20% weightadd-on of the above polymer mixtures in accordance with the practice ofthis invention. The fabrics were cured at 350° F. (176° C.) for 26seconds. The samples were then examined with scattering electronmicroscopy (SEM). The results appear in FIG. 6f and are discussed in thefollowing examples explaining the SEM figures.

EXAMPLE 28

Description of Fabric Controlled Placement Through Scanning ElectronMicroscope (SEM) Photomicrographs

FIG. 6a depicts a cut end of a filament illustrating a thin filmencapsulation in white. A crack was created in the filament with a hightemperature electron beam. This crack continues under the surface of thethin film. The filament has been cut and the thin film has beenstretched or elasticized by the cutting of the filament. The two arrowsin the upper right corner show the thickness or distance represented bythe black box in the lower right corner as 126 nm.

FIG. 6b depicts an isolated image on 330 Denier Cordura single filamentfiber processed with the micro-finish fiber coating technology,magnified 5,720 times. The Bioengineered Comfort™ polymer containingengineered protein and solid silicone was used in the process with amoderate degree of shear. The image on top of the fiber is anundispensed protein polymer which clearly illustrates the presence ofthe protein after the micro-finish fiber coating process. The surfacemorphology has very small protein polymer particles encapsulated in thesolid silicone polymer and is homogeneously dispersed throughout thefilm system on the fiber.

FIG. 6c is an image of a white nylon magnified 178 times. Theapplication side is shown at the bottom left hand corner of the image.The upper portion of the image is the non-application side. At the upperright corner is the intersection of the warp and fill fiber bundles,where the polymer presence can clearly be seen on the fibers. Theinternal layer of polymer that creates the liquid barrier or resistantproperty can be seen along the bottom right corner of the picture. Thisinternal layer is a combination of polymer filling some interstitialspaces and polymer "glueing" together the fibers and filaments of theweb.

FIG. 6d depicts the surface of a circular fiber that has had a defractedbroad electron beam of approximately 2000 degree centigrade defractedacross the image area. The imaging shows a destructive burn pattern of afluorochemical package on the surface of the siloxane film. On thesurface of the filament the image depicts the surface migration of thefluorochemical from the fiber through the thin film and oriented on thesurface of the silicone.

FIG. 6e is a Tunneling Electron Microscopy (TEM) image of a thin crosssection of a filament encapsulated with polymer. The lighter image onthe lower side of the frame is a polyester filament. The black sphericaldots on the outer edge of the fiber are extremely dense processedmaterial. In this imaging technique, the darker the image, the denserthat specific material.

FIG. 6f depicts a nylon fabric magnified 419 times with bright particletracer images and a cross sectional image of a nylon fabric. Thesebright particles are submicron metal particles dispersed throughout thefabric in the processed film. The addition of bright copper submicronparticles in the polymer allows secondary back scatter mode toillustrate the complete encapsulation ability of the controlledplacement technology. The left side of the image is the performance sideof the fabric which is the non-application side of the polymer, but itis clear, with the presence of the glowing brightness of the coppersubmicron particles throughout the performance side of the fabric, thatcontrolled placement technology successfully encapsulates completelyaround the fibers throughout the fabric structure. The other clearunique feature of the controlled placement technology is that each fiberis still independent. This differentiation allows the controlledplacement technology's processed fabrics to retain exceptional hand andtactile quality, while still imparting performance characteristics. Onthe left side of the fabric, directly underneath the printed text"performance side", an elemental analysis was conducted and the outcomeof that analysis is depicted in FIG. 6g. The result clearly shows astrong presence of submicron copper particles.

In the next examples that involve accelerated weathering, abrasion,water repellency, moisture penetration, and rain testing, data isprovided for a Tactel fabric identified as Deva Blue. The fabric is 100%nylon, available from Arthur Kahn and identical in composition,preparation, and enveloping specification to that of the Hot Coralpresented in previous examples.

EXAMPLE 29

Accelerated Weathering Test

The results of weathering upon a treated web of this invention are shownin actual tested sample pieces comparing original fabrics withembodiments of the enveloped fiber fabrics of this invention.

In every case, the enveloped fiber fabric samples were found to havesignificantly better weathering characteristics than the originaluntreated fabrics as determined by accelerated weathering tests. Eventhe reverse side (compared to the treated side) of an enveloped fibernylon fabric of the Tactel® type was improved over the original fabric.In addition, the excellent "hand" of the enveloped fiber fabric wasfound to have been maintained after the accelerated weathering test.

The test performed conforms to each of the following performancestandards:

ASTM G-53 light/water exposure materials

ASTM D-4329 light/water exposure-plastics

General Motors Test spec TM-58-10

ISO 4892 Plastics exposure to lab light

The procedure used for the accelerated weathering testing involvedsubjecting fabric samples to four hours of high-intensity ultravioletlight, alternating continuously with four hours of water condensation,wetting the fabric in the dark. This alternating exposure (four hourson, four hours off) to high-intensity ultraviolet light and waterwetting, simulates outdoor environmental conditions in a vastlyaccelerated manner, quickly degrading unprotected dyes and fibers. Themethods and apparatus used for this test was a QUV AcceleratedWeathering Tester from The Q-Panel Company, 26200 First Street,Cleveland, Ohio 44145.

The results obtained on some sample fabrics are expressed in Table VII.In this Table, results are expressed in the form of "A/B" where A and Bare numbers. The number "A" is the color rating on a graduated scalefrom 0 to 10. The number 10 equals perfect (original) condition where 0equals a white color and a completely faded fabric. The number "B" isthe number of hours of weathering transpiring when the number "A" ratingwas obtained.

                                      TABLE IX                                    __________________________________________________________________________    Accelerated Weathering Testing                                                                                    COLOR                                                                         RATING                                                                        (rating/hours)                                     ORIGINAL ENVELOPED                                                                              REVERSE  10 = Perfect                              ORIGINAL FABRIC   FABRIC   SIDE     0 = white color                           FABRIC   WEATHERED                                                                              WEATHERED                                                                              WEATHERED                                                                              fades out                                 __________________________________________________________________________    TACTEL ®                                                                           3/159    8/159             After 159 hrs.,                           Deva Blue 9-                        enveloped fabric                          420-6-1                             significantly less                        10/0                                weathered than                                                                original; original                                                            nearly white;                                                                 enveloped fabric                                                              still light blue.                         TACTEL.sub.-- Hot                                                                      5/24     10/24    9/24     After 24 hrs.,                            Coral 9-420-6-2                     enveloped fabric                          (AKA 18)                            is significantly                          10/0                                less weathered                                                                than original, as                                                             was reverse side.                         __________________________________________________________________________

EXAMPLE 30

Abrasion Resistance Testing

The results of abrasion resisting testing clearly show that envelopedfiber fabrics of this invention have superior wear characteristicscompared to the untreated original (starting) fabrics. In most cases,the enveloped fiber fabric samples underwent twice as many cycles as theuntreated samples without evidencing tearing in the samples. Suchresults can be explained by theorizing that the envelopment withsilicone polymer of the yarns and fibers comprising a fabric, providessuch treated yarns and fibers with a lubricity agent so that abrasiveaction was minimized and the integrity of the fabric was preservedsignificantly longer. The anti-abrasion characteristics also applied tothe minimized effects of one fiber rubbing against another fiber, or ofone yarn against another yarn.

This experiment compared the abrasion resistance of embodiments of theenveloped fiber fabrics of this invention with untreated fabrics. Thedurability of each fabric test specimen was determined by the TaberAbraser. Each specimen is abraded for the number of cycles indicated.Comparisons were then made between the enveloped fiber fabrics of theinvention and untreated fabrics. Specifically, this test method utilizesthe Taber Abraser No. 174. An important feature of this abrader was thatits wheels traverse a complete circle on the test specimen surface.Thus, the surface was abraded at all possible angles relative to theweave or grain of the specimen. Comparisons of the enveloped fiberfabric to the untreated fabric were based upon a scale 0 through 10,where 0 was a completely torn specimen, and 10 was the new (or starting)sample.

Each test procedure used a single 7 inch diameter fiber enveloped fabricspecimen, and a single 7 inch diameter original (untreated) fabricspecimen. The procedure used was as follows:

1. A test specimen of the fiber enveloped fabric with a 7 inch diameterwas cut.

2. An equally-sized specimen of control (untreated) fabric was cut.

3. The fabric specimen was mounted on the rotating wheel securely andthe clamps were screwed down.

4. The counter was set.

5. The vacuum power adjustment was set. (For this experiment, vacuum wasset at 80.)

6. The abraser was started.

7. At the procedurally specified number of revolutions, the abraser wasstopped and each fabric sample was rated at a value between 0 and 10.

Illustrative results of the test on some sample fabrics are shown inTable X.

Abrasion Testing Numeric Grade of Abrasion 0-10

0--Total failure of fabric specimen. Fibers are torn apart

5--Fabric specimen is starting to tear. Fabric is noticeably thinner

10--Original unabraded fabric specimen

                  TABLE X                                                         ______________________________________                                                 UNTREATED  ENCAPSULATED                                              SPECIMENS                                                                              FABRIC     FABRIC       COMMENTS                                     ______________________________________                                        Hot Coral                                                                              5          7            Untreated                                    Tactel   1,000 cyc. 1,000 cyc.   sample is                                                                     starting to tear,                                                             and enveloped                                                                 sample was                                                                    still intact.                                Deva Blue                                                                              4          7            Visible rips                                 Tactel   1,000 cyc. 1,000 cyc.   in untreated                                                                  sample.                                                                       Enveloped                                                                     sample fibers                                                                 were frayed.                                 ______________________________________                                    

EXAMPLE 31

Breathability Testing

This test procedure followed the Modified ASTM E96-8 test. As shown bythe results of this testing in the following Table, the fiber envelopedfabrics of this invention were found to have high breathability. Thisbreathability was in excess of that needed to remove the average valueof several thousand grams of perspiration generated daily by the humanbody. The results for the fiber enveloped fabrics of this invention weregenerally superior to the corresponding results measured under the sameconditions for prior art treated fabrics, such as the Gore-Tex® brandfabric.

Breathability of a fabric sample was determined by accurately weighingthe amount of water passing through such fabric sample under carefullycontrolled temperature and relative humidity conditions in anenvironmental chamber. The water weight loss from a cup whose mouth issealed with a fabric sample was expressed as grams of water vapor persquare meter of fabric per 24 hour day.

In an attempt to more realistically simulate what is actually occurringinside the apparel during exercise, a specially designed test wasperformed to measure outward water vapor transport (MVTR) in a "Bellows"effect. The test simulates the high volumes of moisture and air that mixwithin a garment that pass outward through it as air is drawn inresultant from activity. The enveloped fabrics of this invention werefound to provide increased performance at a higher activity, or airexchange level than is achievable with corresponding untreated fabrics.

The "Bellows" MVTR breathability test was run inside of a controlledtemperature/humidity chamber similar to the foregoing cup test. However,instead of a standard cup, each fabric sample was sealed over the opentop of a special cup which was provided with an air inlet aperture inits bottom, thereby allowing air to be bubbled up through the sealedcontainer at a controlled rate. A check valve at the air inlet operationprevents backup or loss of water from the container. The air bubblespassed upwardly through the water and out through the fabric samplemounted sealingly across the cup top along with the water vapor. TableXI illustrates some representation results obtained.

                  TABLE XI                                                        ______________________________________                                        Moisture Vapor Transport (MVTR)                                               FABRIC               MVTR.sup.(1)                                             ______________________________________                                        Made by a Method of the Invention                                                                  13,600                                                   Enveloped fiber fabric, Hot Coral                                             Tactel ®                                                                  Commercial Products  10,711                                                   Gore-Tex\3-Ply Fabric                                               ______________________________________                                         Table Footnote:                                                               .sup.(1) MVTR here references moisture vapor transport through a fabric       sample as measured by the "Bellows" test with air delivered to the bubble     at 2 to 4 psi air pressure, in an Environmental Chamber at 100 to             102° F. and 38-42% relative humidity. MVTR is expressed as grams o     water per square meter of surface per 24 hour day.                       

The MVTR data shown below is an example of a web where thefluorochemical is blooming from the fibers through the silicone thinfilm and re-orienting on the surface of the thin film. This data showsno significant reduction in moisture vapor transport rate with afluorochemical additive on the surface of the silicone. The siliconepolymer composition used was GE 6108 A:B (1:1), with 19.51% weightadd-on, and the durable water repellent (DWR) was a fluorochemicalcomposition that was added to the web as a pre-treatment.

                  TABLE XII                                                       ______________________________________                                        MVTR Results of Web Treated with a Fluorochemical Additive                    FABRIC              MVTR (g/m.sup.2 · day)                           ______________________________________                                        Untreated Versatec, Passion Fruit                                                                 1681.67                                                   (M032195A1E)                                                                  Treated Versatec + GE6108 + DWR                                                                   1444.99                                                   ______________________________________                                    

EXAMPLE 32

Water Repellency: Spray Testing

Water repellency spray testing is carried out according to AATCC TestMethod 22-1974. The results of such testing show that the fiberenveloped Tactel®-type fabrics of the invention show excellent initialspray ratings initially, as do the original untreated fabrics which havebeen treated with water repellent chemicals such as fluorochemicals.Specifically, as the results shown below demonstrate, after ten machinewashes, the treated side of a fiber enveloped fabric of the inventionwas found to remain highly water repellent, while, on the reverse sidethereof, the original water repellency rating was found to have fallensignificantly. The water repellency spray rating on the untreated fabricfell even more drastically. Excellent "hand" was retained after thetest. It is believed that pretreatment with a fluorochemical having goodwater repellent properties can augment and even synergistically coactwith the silicone resin used to produce fiber enveloped fabrics of thisinvention to produce superior spray ratings in such a fiber. The resultsare shown in Table XIII.

This test method is believed to be applicable to any textile fabric,whether or not it has been given a water resistant or water-repellentfinish. The purpose of the test is to measure the resistance of fabricsto wetting by measuring the water-repellent efficiency of finishesapplied to fabrics, particularly to plain woven fabrics. The portabilityand simplicity of the instrument, and the shortness and simplicity ofthe test procedure, make this method of test especially suitable formill production control work. This test method is not intended, however,for use in predicting the probable rain penetration resistance offabrics, since it does not measure penetration of water through thefabric.

The results obtained with this test method are believed to dependprimarily on the resistance to wetting, or the water repellency, of thefibers and yarns comprising a fabric, and not upon the construction ofthe fabric. This test involves spraying water against the taut surfaceof a test fabric specimen under controlled conditions which produce awetted pattern whose size depends on the relative water repellency ofthe fabric. Evaluation is accomplished by comparing the wetted patternwith pictures on a standard chart. The methods and apparatus andmaterials employed for this test were an AATCC Spray Tester, a beaker,distilled water, and the specimen fabrics.

The procedure followed for this test was as follows: a test specimen,which had been conditioned as procedurally directed, was fastenedsecurely in a 15.2 cm (6") metal hoop so that it presented a smoothwrinklefree surface. The hoop was then placed on the stand of the testerso that the fabric was uppermost in such a position that the center ofthe spray pattern coincided with the center of the hoop. In the case oftwills, gabardines, piques or fabrics of similar ribbed construction,the hoop was placed on the stand in such a way that the ribs werediagonal to the flow of water running off the fabric specimen.

250 milliliters (ml) of distilled water at 27° C. ±1° C. (80° F. ±2° F.)was poured into the funnel of the tester and allowed to spray onto thetest specimen, which took approximately 25 to 30 seconds. Uponcompletion of the spraying period, the hoop was taken by one edge andthe opposite edge tapped smartly once against a solid object, with thefabric facing the object. The hoop was then rotated 180 degrees and thentapped once more on the location previously held.

The procedure and methods and apparatus of this test were slightlymodified from the specifications, as follows:

1. The spray nozzle holes were slightly larger than specified, but theflow rate of the nozzle was 250 ml/30 sec., as required.

2. The number of taps of the hoop was two instead of one.

For each wash test, a fabric sample was washed using a warm wash/coldrinse cycle with one cup of Tide® detergent and dried at a hot/dry cyclein a dryer, unless otherwise indicated. The test results were evaluatedby comparing the wet or spotted pattern on the fabric sample aftertapping the hoop with the standard rating chart. Results producedsurface wetting, with no water completely soaking through the testfabric sample. The numbers were ratings based upon the standard chart.Such values are thus subjective deductions by an experiencedexperimenter.

                                      TABLE XIII                                  __________________________________________________________________________    Spray Test Results                                                            ORIGINAL                                                                              TREATED WEBS OF THE INVENTION                                         FABRIC  Initial           After 100 Washes                                    Web Type &  Application                                                                         Non-Application Non-Application                             Number  Initial                                                                           Side  Side    Application Side                                                                      Side                                        __________________________________________________________________________    Supplex 100 100   100     70      80                                          H053194C                                                                      Med Blue 4040                                                                         100 100   100     90      90                                          M082994B-1E                                                                   Yellow 4040                                                                           100 100   100     90      90                                          M083094B-1B                                                                   __________________________________________________________________________

EXAMPLE 33

Moisture Penetration Test

The results shown in the Table below demonstrate that all of the fiberenveloped fabrics of this invention test were significantly better thanthe original untreated fabrics with regard to resisting the penetrationof water under the test conditions used. After the test, the "hand" ofthe tested fabric samples remained excellent.

The purpose of this test was to evaluate how well a fabric stands up towetness under continuous pressure, such as kneeling on the ground, orsitting in a wet chairlift, for a period of 30 minutes. This testinvolves placing both a fabric sample and a standard blotter sample ontop of a water container which contains 700 ml of tap water. The fabricsample and the blotter sample are each then subjected to a continuouspressure of 87 lbs. distributed evenly over 100 square inches of surfacearea for a period of 30 minutes. After this time, a visual inspection ofthe fabric is made for any water penetration, and the paper blotter isweighed to detect water gain or penetration.

The methods and apparatus employed for each such test was one 20 inchdiameter aluminum pan, one 87 lbs. weight distributed evenly over 100square inches of fabric, one paper blotter, 700 ml water, miscellaneousfabric scraps for cushioning and the test fabric sample pieces.

Paper blotter dry weight: 4.7 gm

Total weight applied to fabric: 87 lbs.

Pressure evenly distributed over surface area of: 100 sq. in.

Pressure: 0.87 lbs./sq. in

The procedure observed for this test was as follows:

1. 700 ml tap water was placed in the round pan.

2. The fabric sample was placed with one side facing the water.

3. One piece of dry blotter paper was placed over the fabric to coverthe pan.

4. Scrap fabric was placed over the blotter paper to cushion the weight.

5. The 87 lb. weight was distributed evenly over the 100-square-incharea.

6. This assembly was left undisturbed for 30 minutes.

7. After this time period, the visual results were recorded.

                                      TABLE XIV                                   __________________________________________________________________________    Fiber Enveloped Fabric of the Invention                                                 ENVELOPE SIDE                                                                            NON-ENVELOPED                                            FABRIC SAMPLE                                                                           OF FABRIC  SIDE OF FABRIC                                                                           CONTROL                                       AND THICKNESS                                                                           FACING WATER                                                                             FACING WATER                                                                             FABRIC                                        __________________________________________________________________________    Deva Blue No water penetration                                                                     No water penetration                                                                     Failure - total                               Tactel ®                                                                            through the fabric.                                                                      through the fabric.                                                                      saturation of                                 0.009 microns                                                                           No visible water spots.                                                                  No visible water spots.                                                                  fabric and blotter.                                     Paper weight = 4.7 gm                                                                    Paper weight = 4.7 gm                                              Water gain = 0.0 gm                                                                      Water gain = 0.0 gm                                      __________________________________________________________________________

EXAMPLE 34

Rain Test

In this testing, the rain test procedure of AATCC Method 35-1985 wasfollowed.

The rain test results obtained demonstrate the clear superiority of thefiber enveloped fabric of the present invention as compared to theoriginal untreated fabric. The data in the Table below shows that fiberenveloped fabrics pass this test by allowing virtually no water to passtherethrough. This result is comparable to the results obtained withhigher cost so-called breathable waterproof fabrics currentlycommercially available in the market. In contrast, the original,untreated fabrics fail to pass this test because they demonstratecomplete saturation. The fiber enveloped fabric samples retain excellent"hand" after the test.

The purpose and scope of this ASTM test is to evaluate resistance of afiber enveloped fabric to water under simulated storm conditions. Thetest specifies that a test fabric is stormproof if less than one gram ofwater is absorbed by blotter paper with a shower head pressure of 3 feetexerted for 5 minutes. This test method is applicable to any textilefabric, whether or not it has a water repellent finish. It measures theresistance of a fabric to the penetration of water by impact, and thuscan be used to predict the probably rain penetration resistance of afabric. The results obtained with this method of test depend on thewater repellency of the fibers and yarns in the fabric tested, and onthe construction of the fabric.

This test involves a test specimen backed by a pre-weighed standardblotter. The assembly is sprayed with water for 5 minutes undercontrolled conditions. The blotter then is separated and weighted todetermine the amount of water, if any, which has leaked through thespecimen fabric during the test and has been absorbed by the blotter.

The methods and apparatus and materials employed in each test were amodified rain tester, blotter paper, water at 80° F. ±2° F., alaboratory balance, 8"×8" fabric specimens which had beenpre-conditioned in an atmosphere of 65% (±2%) relative humidity and 70°F. (±2° F.) for four hours before testing, and tape.

The procedure followed for this test was as follows:

1. A 6"×6" paper blotter was weighted to the nearest 0.1 gm and placedbehind the test specimen.

2. The test fabric with the paper blotter in registration therewith wastaped on the specimen holder.

3. A tube in the rain tester was filled with water up to the 3 footlevel. It was confirmed that water was flowing out of the overflow tubewhich maintains the 3 foot column of water.

4. The water spray distance from the tip of the nozzle to the specimenholder was measured and adjusted to 12 inches.

5. The specimen holder was left in place and the rain tester was turnedon for five minutes.

6. After the test period, the paper blotter was removed and reweighed tothe nearest 0.1 gm.

The results of the test selected fabric samples are shown in Table XV.

                  TABLE XV                                                        ______________________________________                                        Rain Test: Grams of Water Penetrating the Fabric                                            ORIGINAL   AFTER 5   AFTER 10                                                 NOT        MACHINE   MACHINE                                    FABRIC SAMPLE WASHED     WASHES    WASHES                                     ______________________________________                                        Hot Coral Tactel ®                                                                      0          0         0                                          Deva Blue Tactel ®                                                                      0          0         0                                          Prior Art Treated Fabrics                                                     Ultrex ®  0          --        0.1                                        Gore-Tex ®                                                                              0          0         --                                         ______________________________________                                    

Original Fabrics--Water Repellant Chemicals Only. No Encapsulation

Hot Coral Tactel/Failed-saturated

Deva Blue Tactel/Failed-saturated

EXAMPLE 35

Viral Penetration Tests (ASTM ES22)

This example demonstrates the ability of the barrier webs of the presentinvention to prevent the penetration of bloodborne pathogens. Thetreated web samples are tested according to ASTM ES 22 (1995). Thepathogenic viruses that are of particular concern are the hepatitus Bvirus (HBV), hepatitus C (HCV) and the human immunodeficiency virus andrelated viruses (HIV). In the assay used in this example, a θ×174bacteriophage was used as the viral particle. An ASTM F903 ChemicalPenetration Cell apparatus was used to measure the penetration of theθ×174 bacteriophage through the barrier web.

Sterile test samples are placed in the Penetration Cell apparatus andchallenged with the θ×174 bacteriophage under various pressures andpenetration of the viral particle was measured. At the conclusion of thetest, the observed side of the article is rinsed with a sterile mediumand then tested for the presence of θ×174 bacteriophage.

HBV, HCV, and HIV range in size from 27 nm to approximately 110 nm. HCVis the smallest at 27 nm to 30 nm, HBV is 42-47 nm and HIV is 80 to 110nm. All the viruses have a spherical or icosahedral structure. The θ×174bacteriophage has a diameter of between approximately 25 to 27 nm and isalso icosahedral or nearly spherical. θ×174 bacteriophage grows rapidlyand can be grown to very high titers.

The surface tension of blood and body fluid is between approximately 42to 60 dynes/cm. To provide for a similar wetting characteristic, thesurface tension of the θ×174 bacteriophage suspension is adjusted toapproximately 40 to 44 dynes/cm using the surfactant Tween 80.

The web samples were treated to minimize viral penetration. Thickerinternal layers or encapsulating films result in better viral barriertest results, but lower breatability. However, the treated webs showedbreatability when worn all day by lab technicians. The results are shownin the following table:

                  TABLE XVI                                                       ______________________________________                                                       Challenge Concentration                                                                        ES22                                          Sample         (Plaque forming units/ml                                                                       Result                                        ______________________________________                                        4040 + GE6108 polymer                                                                        7 × 10.sup.8                                                                             Pass                                          (53.3% wt. add on                                                             4040 + LIM 6060 polymer                                                                      7 × 10.sup.8                                                                             Pass                                          (87.6% wt. add on                                                             C.sup.3 fabric + polymer (22-                                                                1.5 × 10.sup.8                                                                           Pass                                          35% wt add on                                                                 Lot #8253 (Nelson Labs                                                                       1.36 × 10.sup.8                                                                          Pass                                          ______________________________________                                    

"LIM" is the acronym for Liquid Injected Molding. All ES22 tests wereperformed by either MO Bio Laboratories, Solana Beach, Calif. or NelsonLaboratories, Inc., Salt Lake City, Utah. Sample materials were testedin triplicate using the ES22 barrier test as defined by ASTM. For amaterial to be considered a viral barrier, all three of the triplicatesamples must pass. Tween 80

EXAMPLE 36

Bacteria Penetration Tests (Modified ASTM ES 22)

This example demonstrates the ability of webs treated in accordance withthis invention to prevent the penetration of bacteria. Bacteria isgenerally larger in size than viruses. A modified ASTM ES 22 testdescribed in the previous example was used to test for bacteriapenetration. The test was modified to use Escherichia coli (E. coli)ATCC number 25922 bacteria and a different agar solution as the nutrientbroth. The media used consisted of the following:

Nutrient Broth:

Beef Extract . . . 3.0 g

Pancreatic digest of gelatin . . . 5.0 g

Potassium Chloride . . . 5.0 g

Calcium Chloride . . . 0.2 g

Distilled water to . . . 1000 ml

Adjust pH to 7.2-7.4 with 2.5 N Sodium Hydroxide and sterilize (40μl/liter)

Nutrient Broth with 0.01% Tween® 80:

Same formula as above with 0.1 ml of Tween® 80 and 45 μl/liter of NaOHadded.

Nutrient Broth with 0.1 % Tween® 80:

Same formula as above with 1.0 ml of Tween® 80 and 45 μl/liter of NaOHadded.

E. coli ATCC 25922 is MUG positive. The organism will fluoresce whengrown on MacConkey Agar plate with MUG (Methylmbelliferylβ-D-Galactoside). The fluoresence provided a measure of selectivity forthe assay. The fabric was challenged with E. coli ATCC strain 25922.Following the challenge, the unchallenged side was assayed forpenetration of the E. coli. E. coli ranges in size from 0.5 to 3.0microns. The results of the tests are shown below.

                  TABLE XVII                                                      ______________________________________                                        Bacterial Penetration Test Results                                                             Challenge   Modified ES22                                    Sample           Concentration                                                                             Result                                           ______________________________________                                        Burlington 40/40 fabric + 23.45%                                                               6 × 10.sup.8                                                                        Pass                                             wt. add on GE6108 polymer                                                     (sample H051995-N)                                                            Burlington 40/40 fabric + 28.11%                                                               6 × 10.sup.8                                                                        Pass                                             wt. add on GE6108 polymer                                                     (sample H051995-I)                                                            ______________________________________                                    

MO BIO Laboratories, Solana Beach, Calif., performed all of thebacterial barrier tests.

EXAMPLE 37

Synthetic Blood Barrier Test

This example demonstrates the ability of webs treated in accordance withthis invention to prevent the penetration of a blood-like fluid(synthetic blood). The treated web samples were tested according to amodified ASTM ES 21 Synthetic Blood Direct Pressure Draft Test Method(ASTM F23, 40, 04). Fabric samples of C³ fabric were treated accordingto the practice of this invention to yield a fabric with 22-35% polymerweight add-on. The synthetic blood came from Jamar Health Products (PhilJohnson), Lot 220. The surface tension of the synthetic blood is 40dynes/cm. According to the test procedure, synthetic blood is pressedagainst a fabric sample at increasing pressures at one spot untilwicking of the fabric occurs. The final pressure is determined by overpressuring to create failure and then backing off at different sitesuntil a pass occurs as per ASTM protocol F23, 40, 04 draft test method.This particular treated fabric (Sample #111193B) passed at 80 psi. Nowicking occurred after one hour of elapsed time.

EXAMPLE 38

Cell Growth Promotion

This example shows the ability to bind growth factors to the polymercomposition incorporated into webs of according to the presentinvention. The growth factor used in this example is PRONECTIN F,produced by Protein Polymer Technologies, Inc. (PPT), San Diego, Calif.PRONECTIN F is a substrate for receptor-specific cell attachment and isa protein polymer produced by bacterial fermentation. PRONECTIN Fconsists of 10% solids and 90% PRONECTIN F diluent. PRONECTIN F providesincreased cell growth compared to traditional growth factors such asfibronectin.

Four 6"×6" samples were prepared:

1. A control sample containing no polymer and no growth factors, acontrol sample containing polymer but no growth factors

2. a sample containing polymer and Fibronectin

3. a sample containing polymer and PRONECTIN F

Each of the samples containing a growth factor were prepared in thefollowing manner:

1. Dow Corning 2303 silicone polymer plus an accelerator were mixed withthe growth factor in a sufficient quantity to produce a final web having17% weight add on polymer and 3% weight add on growth factor.

2. The web was a 3.2 oz. nylon web and was stretched.

3. The polymer mixture was applied to the surface of the web and ashearing knife was pulled across the web to shear thin the polymermixture, place it into the web, and extract some of it out of the web.This procedure is commonly referred to as a "hand pull."

4. The treated webs were then cured in an oven for 20 seconds at 220° F.(a temperature and time small enough to ensure that the growth factorswere not damaged).

5. The cured samples were then put aside for 2 hours.

The samples produced by the procedure above were then rinsed withserum-free growth medium to promote cell growth without othercontaminants. The samples were then challenged with seed cells of HeLawhich is a human cervical mammalian cell. The cells grown were thendislodged by standard trypsinization protocols and counted.

The end result was that webs treated in accordance with this invention,where PRONECTIN F was added, showed a 60-100% increase in cell growthover traditional fibronectin cell growth promoters and a much largergrowth increase over samples containing no growth factors.

It should be understood, of course, that the foregoing relates only topreferred embodiments of the present invention and that numerousmodifications or alterations may be made therein without departing fromthe spirit and the scope of the invention as set forth in the appendedclaims.

What is claimed is:
 1. An absorbent garment comprising:an absorbent pad;and at least one layer of a web, wherein the web comprises a pluralityof web members with interstices therebetween and an at least partiallycured polymer composition derived from a shear-thinable thixotropicpolymer, wherein the web is adapted to be, when the polymer is in thefully cured state: substantially impermeable to liquids; permeable toselective gases; and substantially impermeable to selective biologicalmaterials due to the presence in the cured polymer of one or moremodifiers capable of interacting with the biological materials.
 2. Theabsorbent garment of claim 1, wherein the biological materials aremicroorganisms.
 3. The absorbent garment of claim 1, wherein thebiological materials are cells.
 4. The absorbent garment of claim 2,wherein the microorganisms are selected from the group consisting offungi, bacteria, viruses and protozoa.
 5. The absorbent garment of claim1, wherein the modifier is an antimicrobial agent.
 6. The absorbentgarment of claim 5, wherein the antimicrobial agent is selected from thegroup consisting of antibacterial agents, antiviral agents, antifungalagents and antiprotozoal agents.
 7. The absorbent garment of claim 6,wherein the antimicrobial agent is selected from the group consisting ofisoniazid, ethambutol, pyrazinamide, streptomycin, clofazimine,rifabutin, fluoroquinolones, ofloxacin, sparfloxacin, rifampin, dapsone,tetracycline, doxycyline, erythromycin, ciprofloxacin, doxycycline,ampicillin, amphotericin B, ketoconazole, fluconazole, pyrimethamine,sulfadiazine, clindamycin, lincomycin, azithromycin, clarithromycin,pentamidine, atovaquone, paromomycin, diclazaril, acyclovir,trifluorouridine, foscarnet, and ganciclovir.
 8. The absorbent garmentof claim 1, wherein the modifier has reactively available sites capableof binding an agent.
 9. The absorbent garment of claim 8, wherein themodifier is urethane.
 10. The absorbent garment of claim 9, wherein theagent is iodine.
 11. The absorbent garment of claim 10, wherein theiodine is reversibly bound to the urethane.
 12. The absorbent garment ofclaim 1, wherein the shear-thinable thixotropic polymer was selectedfrom the group consisting of silicones, polyurethanes, fluorosilicones,modified polyurethane silicones, modified silicone polyurethanes,acrylics, and polytetrafluoroethylene or combinations thereof.
 13. Theabsorbent garment of claim 1, wherein the web is selected from the groupconsisting of cotton, wool, silk, jute, linen, rayon, acetate,polyesters, polyethyleneterephthalate, polyamides, nylon, acrylics,olefins, aramids, azlons, glasses, modacrylics, novoloids, nytrils,rayons, sarans, spandex, vinal, vinyon, foams, films, foamed sheets,natural leathers, split hydes, synthetic leathers, vinyl, urethane,filtration membranes, polysulfones, polyimides, nitrocellulose,cellulose acetate, cellulose, and regenerated cellulose or combinationsthereof.
 14. The absorbent garment of claim 1, wherein the liquid isbodily fluid.
 15. The absorbent garment of claim 14, wherein the bodilyfluid is selected from the group consisting of saliva, gingivalsecretions, cerebrospinal fluid, gastrointestinal fluid, mucous,urogenital secretions, synovial fluid, blood, serum, plasma, urine,cystic fluid, lymph fluid, ascites, pleural effusion, interstitialfluid, intracellular fluid, ocular fluids, seminal fluid, mammarysecretions, vitreal fluid, and nasal secretions.
 16. The absorbentgarment of claim 14, wherein the bodily fluid is blood.
 17. Theabsorbent garment of claim 14, wherein the bodily fluid is urine. 18.The absorbent garment of claims 1, wherein the garment is an incontinentbrief.
 19. The absorbent garment of claim 18, wherein the incontinentbrief further contains a shedding shield that is positioned next to theskin of the wearer.
 20. The absorbent garment of claim 19, wherein theabsorbent pad in the incontinent brief is under the shedding shield. 21.The absorbent garment of claim 20, wherein the absorbent pad is largerthan the shedding shield.
 22. The absorbent garment of claim 20, whereinthe absorbent pad is smaller than the shedding shield.
 23. The absorbentgarment of claim 18, wherein there are a plurality of absorbent pads.